LOANS - Allowance for loan losses (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2016
Dec. 31, 2015
Changes in allowance for loan losses :                          
Beginning balance       $ 15,988       $ 12,300 $ 15,988 $ 12,300 $ 23,672    
Provision for loan losses $ 2,445 $ 1,392 $ 629 1,125 $ 1,052 $ 6,699 $ 2,379 997 5,591 11,127 92    
Charge-offs                 (7,736) (9,657) (12,096)    
Recoveries                 1,019 2,218 632    
Ending balance 14,862       15,988       14,862 15,988 12,300    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans individually evaluated for impairment                       $ 1,844 $ 2,696
Loans collectively evaluated for impairment                       338 298
Non-impaired loans collectively evaluated for impairment                       11,562 11,099
Loans acquired with deteriorated credit quality                       1,118 1,895
Total 14,862     15,988 15,988     12,300 15,988 12,300 23,672 14,862 15,988
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans individually evaluated for impairment                       28,432 22,528
Impaired loans collectively evaluated for impairment                       3,171 2,363
Non-impaired loans collectively evaluated for impairment                       2,260,117 1,932,221
Loans acquired with deteriorated credit quality                       28,256 38,477
Total loans                       2,319,976 1,995,589
Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       1,604,767 1,526,623
Commercial | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       457,827 499,573
Non residential real estate | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       969,615 876,784
Construction and land development | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       177,325 150,266
Residential real estate | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       253,713 163,224
Consumer | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       270,017 161,512
Lease financing | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       191,479 144,230
Non-PCI loans                          
Changes in allowance for loan losses :                          
Beginning balance       14,093       10,503 14,093 10,503 11,985    
Provision for loan losses                 6,425 11,061 300    
Charge-offs                 (7,668) (9,565) (2,271)    
Recoveries                 894 2,094 489    
Ending balance 13,744       14,093       13,744 14,093 10,503    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Total 13,744     14,093 14,093     10,503 14,093 10,503 11,985 13,744 14,093
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       2,291,720 1,957,112
Non-PCI loans | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       1,583,380 1,496,396
Non-PCI loans | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       708,340 460,716
Non-PCI loans | Commercial | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       454,310 493,445
Non-PCI loans | Non residential real estate | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       963,895 862,744
Non-PCI loans | Construction and land development | Commercial loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       165,175 140,207
Non-PCI loans | Residential real estate | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       247,156 155,266
Non-PCI loans | Consumer | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       269,705 161,220
Non-PCI loans | Lease financing | Other loan portfolio                          
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       191,479 144,230
PCI loans                          
Changes in allowance for loan losses :                          
Beginning balance       1,895       1,797 1,895 1,797 11,687    
Provision for loan losses                 (834) 66 (208)    
Charge-offs                 (68) (92) (9,825)    
Recoveries                 125 124 143    
Ending balance 1,118       1,895       1,118 1,895 1,797    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Total 1,118     1,895 1,895     1,797 1,895 1,797 11,687 1,118 1,895
Recorded investment (loan balance) at December 31, 2014:                          
Total loans                       28,256 38,477
PCI loans | Commercial | Commercial loan portfolio                          
Changes in allowance for loan losses :                          
Beginning balance       6,917       2,284 6,917 2,284      
Provision for loan losses                 2,992 11,154      
Charge-offs                 (4,252) (7,742)      
Recoveries                 263 1,221      
Ending balance 5,920       6,917       5,920 6,917 2,284    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans individually evaluated for impairment                       878 1,765
Loans collectively evaluated for impairment                       4 32
Non-impaired loans collectively evaluated for impairment                       4,539 4,745
Loans acquired with deteriorated credit quality                       499 375
Total 5,920     6,917 6,917     2,284 6,917 2,284 2,284 5,920 6,917
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans individually evaluated for impairment                       6,504 6,316
Impaired loans collectively evaluated for impairment                       44 254
Non-impaired loans collectively evaluated for impairment                       447,762 486,875
Loans acquired with deteriorated credit quality                       3,517 6,128
Total loans                       457,827 499,573
PCI loans | Non residential real estate | Commercial loan portfolio                          
Changes in allowance for loan losses :                          
Beginning balance       5,179       6,925 5,179 6,925      
Provision for loan losses                 (1,041) (2,001)      
Charge-offs                 (1,177) (379)      
Recoveries                 264 634      
Ending balance 3,225       5,179       3,225 5,179 6,925    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans individually evaluated for impairment                       296 479
Loans collectively evaluated for impairment                       13 35
Non-impaired loans collectively evaluated for impairment                       2,684 3,662
Loans acquired with deteriorated credit quality                       232 1,003
Total 3,225     5,179 5,179     6,925 5,179 6,925 6,925 3,225 5,179
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans individually evaluated for impairment                       18,275 13,434
Impaired loans collectively evaluated for impairment                       123 283
Non-impaired loans collectively evaluated for impairment                       945,497 849,027
Loans acquired with deteriorated credit quality                       5,720 14,040
Total loans                       969,615 876,784
PCI loans | Construction and land development | Commercial loan portfolio                          
Changes in allowance for loan losses :                          
Beginning balance       435       486 435 486      
Provision for loan losses                 (183) 86      
Charge-offs                 (1) (171)      
Recoveries                 94 34      
Ending balance 345       435       345 435 486    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans individually evaluated for impairment                       6  
Loans collectively evaluated for impairment                       2  
Non-impaired loans collectively evaluated for impairment                       337 419
Loans acquired with deteriorated credit quality                         16
Total 345     435 435     486 435 486 486 345 435
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans individually evaluated for impairment                       63  
Impaired loans collectively evaluated for impairment                       21  
Non-impaired loans collectively evaluated for impairment                       165,091 140,207
Loans acquired with deteriorated credit quality                       12,150 10,059
Total loans                       177,325 150,266
PCI loans | Residential real estate | Other loan portfolio                          
Changes in allowance for loan losses :                          
Beginning balance       2,120       2,038 2,120 2,038      
Provision for loan losses                 1,601 663      
Charge-offs                 (966) (742)      
Recoveries                 174 161      
Ending balance 2,929       2,120       2,929 2,120 2,038    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans individually evaluated for impairment                       379 452
Loans collectively evaluated for impairment                       225 174
Non-impaired loans collectively evaluated for impairment                       1,968 1,000
Loans acquired with deteriorated credit quality                       357 494
Total 2,929     2,120 2,120     2,038 2,120 2,038 2,038 2,929 2,120
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans individually evaluated for impairment                       2,920 2,778
Impaired loans collectively evaluated for impairment                       2,109 1,377
Non-impaired loans collectively evaluated for impairment                       242,127 151,111
Loans acquired with deteriorated credit quality                       6,557 7,958
Total loans                       253,713 163,224
PCI loans | Consumer | Other loan portfolio                          
Changes in allowance for loan losses :                          
Beginning balance       749       567 749 567      
Provision for loan losses                 382 405      
Charge-offs                 (301) (334)      
Recoveries                 100 111      
Ending balance 930       749       930 749 567    
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans collectively evaluated for impairment                       23 7
Non-impaired loans collectively evaluated for impairment                       877 735
Loans acquired with deteriorated credit quality                       30 7
Total 930     749 749     $ 567 749 567 $ 567 930 749
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans collectively evaluated for impairment                       213 51
Non-impaired loans collectively evaluated for impairment                       269,492 161,169
Loans acquired with deteriorated credit quality                       312 292
Total loans                       270,017 161,512
PCI loans | Lease financing | Other loan portfolio                          
Changes in allowance for loan losses :                          
Beginning balance       588         588        
Provision for loan losses                 1,840 820      
Charge-offs                 (1,039) (289)      
Recoveries                 124 57      
Ending balance 1,513       588       1,513 588      
Allowance for loan losses balance at December 31, 2014 attributable to:                          
Loans individually evaluated for impairment                       285  
Loans collectively evaluated for impairment                       71 50
Non-impaired loans collectively evaluated for impairment                       1,157 538
Total $ 1,513     $ 588 $ 588       $ 588 $ 588   1,513 588
Recorded investment (loan balance) at December 31, 2014:                          
Impaired loans individually evaluated for impairment                       670  
Impaired loans collectively evaluated for impairment                       661 398
Non-impaired loans collectively evaluated for impairment                       190,148 143,832
Total loans                       $ 191,479 $ 144,230