LOANS AND ALLOWANCE FOR LOAN LOSSES - Summary of loans by past due status (Details 4) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current $ 1,547,631 $ 873,290
Total loans $ 1,568,907 $ 877,061
Current - As a percent of total loans 98.60% 99.50%
As a percent of total loans 100.00% 100.00%
30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 991 $ 238
Past due - As a percent of total loans 0.10% 0.10%
90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 20,285 $ 3,533
Past due - As a percent of total loans 1.30% 0.40%
Retail & other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current $ 14,500 $ 6,501
Total loans 14,515 6,513
Retail & other | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 15 12
Retail & other | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Commercial Portfolio Segment | Commercial & industrial    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 427,890 294,165
Total loans 428,270 294,419
Commercial Portfolio Segment | Commercial & industrial | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 22 50
Commercial Portfolio Segment | Commercial & industrial | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 358 204
Commercial Portfolio Segment | Owner-occupied CRE    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 357,065 184,334
Total loans 360,227 185,285
Commercial Portfolio Segment | Owner-occupied CRE | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 268
Commercial Portfolio Segment | Owner-occupied CRE | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 2,894 951
Commercial Portfolio Segment | AG Production    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 34,758 14,989
Total loans 34,767 15,018
Commercial Portfolio Segment | AG Production | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 16
Commercial Portfolio Segment | AG Production | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 9 13
Commercial Real Estate Portfolio Segment | AG real estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 45,026 43,042
Total loans 45,234 43,272
Commercial Real Estate Portfolio Segment | AG real estate | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Commercial Real Estate Portfolio Segment | AG real estate | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 208 230
Commercial Real Estate Portfolio Segment | CRE investment    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 183,562 77,671
Total loans 195,879 78,711
Commercial Real Estate Portfolio Segment | CRE investment | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Commercial Real Estate Portfolio Segment | CRE investment | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 12,317 1,040
Commercial Real Estate Portfolio Segment | Construction & land development    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 73,795 36,495
Total loans 74,988 36,775
Commercial Real Estate Portfolio Segment | Construction & land development | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Commercial Real Estate Portfolio Segment | Construction & land development | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 1,193 280
Residential | First mortgage    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 296,828 153,834
Total loans 300,304 154,658
Residential | First mortgage | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 486 150
Residential | First mortgage | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 2,990 674
Residential | Junior mortgage    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 91,075 51,816
Total loans 91,331 51,967
Residential | Junior mortgage | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 200 10
Residential | Junior mortgage | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 56 141
Residential | Residential construction    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 23,132 10,443
Total loans 23,392 10,443
Residential | Residential construction | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Residential | Residential construction | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 260
Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 901,633 739,482
Total loans $ 901,987 $ 740,135
Current - As a percent of total loans 99.80% 99.80%
As a percent of total loans 100.00% 100.00%
Originated | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 97 $ 72
Past due - As a percent of total loans 0.10% 0.10%
Originated | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 257 $ 581
Past due - As a percent of total loans 0.10% 0.10%
Originated | Retail & other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current $ 10,092 $ 6,339
Total loans 10,095 6,351
Originated | Retail & other | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 3 12
Originated | Retail & other | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Originated | Commercial Portfolio Segment | Commercial & industrial    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 330,069 283,924
Total loans 330,073 284,023
Originated | Commercial Portfolio Segment | Commercial & industrial | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 50
Originated | Commercial Portfolio Segment | Commercial & industrial | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 4 49
Originated | Commercial Portfolio Segment | Owner-occupied CRE    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 182,734 153,563
Total loans 182,776 153,563
Originated | Commercial Portfolio Segment | Owner-occupied CRE | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Originated | Commercial Portfolio Segment | Owner-occupied CRE | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 42  
Originated | Commercial Portfolio Segment | AG Production    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 9,185 6,836
Total loans 9,192 6,849
Originated | Commercial Portfolio Segment | AG Production | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Originated | Commercial Portfolio Segment | AG Production | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 7 13
Originated | Commercial Real Estate Portfolio Segment | AG real estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 18,858 25,464
Total loans 18,858 25,464
Originated | Commercial Real Estate Portfolio Segment | AG real estate | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Originated | Commercial Real Estate Portfolio Segment | CRE investment    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 72,930 58,562
Total loans 72,930 58,949
Originated | Commercial Real Estate Portfolio Segment | CRE investment | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Originated | Commercial Real Estate Portfolio Segment | CRE investment | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due   387
Originated | Commercial Real Estate Portfolio Segment | Construction & land development    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 44,147 27,231
Total loans 44,147 27,231
Originated | Commercial Real Estate Portfolio Segment | Construction & land development | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Originated | Residential | First mortgage    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 164,664 122,241
Total loans 164,949 122,373
Originated | Residential | First mortgage | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 81
Originated | Residential | First mortgage | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 204 132
Originated | Residential | Junior mortgage    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 48,186 44,879
Total loans 48,199 44,889
Originated | Residential | Junior mortgage | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 13 10
Originated | Residential | Junior mortgage | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due  
Originated | Residential | Residential construction    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 20,768 10,443
Total loans 20,768 10,443
Originated | Residential | Residential construction | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due  
Originated | Residential | Residential construction | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due  
Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 645,998 133,808
Total loans $ 666,920 $ 136,926
Current - As a percent of total loans 96.90% 97.70%
As a percent of total loans 100.00% 100.00%
Acquired | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 894 $ 166
Past due - As a percent of total loans 0.10% 0.10%
Acquired | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 20,028 $ 2,952
Past due - As a percent of total loans 3.00% 2.20%
Acquired | Retail & other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current $ 4,408 $ 162
Total loans 4,420 162
Acquired | Retail & other | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 12
Acquired | Retail & other | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Acquired | Commercial Portfolio Segment | Commercial & industrial    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 97,821 10,241
Total loans 98,197 10,396
Acquired | Commercial Portfolio Segment | Commercial & industrial | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 22
Acquired | Commercial Portfolio Segment | Commercial & industrial | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 354 155
Acquired | Commercial Portfolio Segment | Owner-occupied CRE    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 174,331 30,771
Total loans 177,451 31,722
Acquired | Commercial Portfolio Segment | Owner-occupied CRE | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 268
Acquired | Commercial Portfolio Segment | Owner-occupied CRE | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 2,852 951
Acquired | Commercial Portfolio Segment | AG Production    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 25,573 8,153
Total loans 25,575 8,169
Acquired | Commercial Portfolio Segment | AG Production | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 16
Acquired | Commercial Portfolio Segment | AG Production | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 2
Acquired | Commercial Real Estate Portfolio Segment | AG real estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 26,168 17,578
Total loans 26,376 17,808
Acquired | Commercial Real Estate Portfolio Segment | AG real estate | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Acquired | Commercial Real Estate Portfolio Segment | AG real estate | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 208 230
Acquired | Commercial Real Estate Portfolio Segment | CRE investment    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 110,632 19,109
Total loans 122,949 19,762
Acquired | Commercial Real Estate Portfolio Segment | CRE investment | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Acquired | Commercial Real Estate Portfolio Segment | CRE investment | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 12,317 653
Acquired | Commercial Real Estate Portfolio Segment | Construction & land development    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 29,648 9,264
Total loans 30,841 9,544
Acquired | Commercial Real Estate Portfolio Segment | Construction & land development | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Acquired | Commercial Real Estate Portfolio Segment | Construction & land development | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 1,193 280
Acquired | Residential | First mortgage    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 132,164 31,593
Total loans 135,355 32,285
Acquired | Residential | First mortgage | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 405 150
Acquired | Residential | First mortgage | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 2,786 542
Acquired | Residential | Junior mortgage    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 42,889 6,937
Total loans 43,132 7,078
Acquired | Residential | Junior mortgage | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 187
Acquired | Residential | Junior mortgage | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due 56 141
Acquired | Residential | Residential construction    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Current 2,364
Total loans 2,624
Acquired | Residential | Residential construction | 30-89 Days Past Due (accruing)    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due
Acquired | Residential | Residential construction | 90 Days & Over or non-accrual    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Past Due $ 260