SEGMENT INFORMATION (Details)
3 Months Ended 12 Months Ended
Dec. 31, 2016
USD ($)
Sep. 30, 2016
USD ($)
Jun. 30, 2016
USD ($)
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Sep. 30, 2015
USD ($)
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Dec. 31, 2016
USD ($)
segment
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Segment Disclosure information                      
Number of operating segments | segment                 4    
Segment information                      
Net interest income $ 41,645,000 $ 39,398,000 $ 35,577,000 $ 39,434,000 $ 32,466,000 $ 31,424,000 $ 31,058,000 $ 29,022,000 $ 156,054,000 $ 123,970,000 $ 112,773,000
Provision for loan and lease losses 5,004,000 2,489,000 1,814,000 5,186,000 2,074,000 2,233,000 904,000 185,000 14,493,000 5,396,000 2,859,000
Net refund transfer fees                 19,240,000 17,388,000 16,130,000
Mortgage banking income                 6,882,000 4,411,000 2,862,000
Program fees                 3,044,000 1,233,000 591,000
Gain on call of security available for sale                   88,000  
Other non interest income                 28,343,000 24,874,000 22,936,000
Total noninterest income 10,485,000 11,301,000 10,802,000 24,921,000 7,717,000 7,806,000 9,485,000 22,986,000 57,509,000 47,994,000 42,519,000
Total non interest expenses 32,166,000 33,534,000 31,866,000 32,541,000 26,847,000 28,238,000 27,165,000 31,074,000 130,107,000 113,324,000 108,118,000
INCOME BEFORE INCOME TAX EXPENSE 14,960,000 14,676,000 12,699,000 26,628,000 11,262,000 8,759,000 12,474,000 20,749,000 68,963,000 53,244,000 44,315,000
Income tax expense (benefit) 4,960,000 4,848,000 4,359,000 8,893,000 3,844,000 3,119,000 4,154,000 6,961,000 23,060,000 18,078,000 15,528,000
NET INCOME 10,000,000 $ 9,828,000 $ 8,340,000 $ 17,735,000 7,418,000 $ 5,640,000 $ 8,320,000 $ 13,788,000 45,903,000 35,166,000 28,787,000
Segment end of period total assets 4,816,309,000       4,230,289,000       $ 4,816,309,000 $ 4,230,289,000 $ 3,747,013,000
Net interest margin (as percent)                 3.65% 3.27% 3.33%
Core Banking Activities                      
Segment Disclosure information                      
Number of operating segments | segment                 3    
Segment information                      
Net interest income                 $ 138,421,000 $ 120,731,000 $ 112,443,000
Provision for loan and lease losses                 3,945,000 3,065,000 3,392,000
Mortgage banking income                 6,882,000 4,411,000 2,862,000
Gain on call of security available for sale                   88,000  
Other non interest income                 26,468,000 23,942,000 21,745,000
Total noninterest income                 33,350,000 28,441,000 24,607,000
Total non interest expenses                 116,190,000 101,184,000 96,451,000
INCOME BEFORE INCOME TAX EXPENSE                 51,636,000 44,923,000 37,207,000
Income tax expense (benefit)                 16,777,000 15,066,000 12,875,000
NET INCOME                 34,859,000 29,857,000 24,332,000
Segment end of period total assets 4,771,926,000       4,205,288,000       $ 4,771,926,000 $ 4,205,288,000 $ 3,735,069,000
Net interest margin (as percent)                 3.30% 3.24% 3.35%
Traditional Banking                      
Segment information                      
Net interest income                 $ 121,692,000 $ 108,303,000 $ 104,832,000
Provision for loan and lease losses                 3,448,000 2,897,000 3,042,000
Gain on call of security available for sale                   88,000  
Other non interest income                 26,090,000 23,670,000 21,489,000
Total noninterest income                 26,090,000 23,758,000 21,489,000
Total non interest expenses                 108,360,000 93,740,000 90,713,000
INCOME BEFORE INCOME TAX EXPENSE                 35,974,000 35,424,000 32,566,000
Income tax expense (benefit)                 11,015,000 11,505,000 11,251,000
NET INCOME                 24,959,000 23,919,000 21,315,000
Segment end of period total assets 4,169,557,000       3,809,526,000       $ 4,169,557,000 $ 3,809,526,000 $ 3,404,323,000
Net interest margin (as percent)                 3.26% 3.20% 3.32%
Warehouse Lending                      
Segment information                      
Net interest income                 $ 16,529,000 $ 12,209,000 $ 7,428,000
Provision for loan and lease losses                 497,000 168,000 350,000
Other non interest income                 18,000 24,000 12,000
Total noninterest income                 18,000 24,000 12,000
Total non interest expenses                 3,142,000 2,526,000 1,857,000
INCOME BEFORE INCOME TAX EXPENSE                 12,908,000 9,539,000 5,233,000
Income tax expense (benefit)                 4,798,000 3,575,000 1,831,000
NET INCOME                 8,110,000 5,964,000 3,402,000
Segment end of period total assets 584,916,000       386,414,000       $ 584,916,000 $ 386,414,000 $ 319,153,000
Net interest margin (as percent)                 3.59% 3.58% 3.77%
Mortgage Banking                      
Segment information                      
Net interest income                 $ 200,000 $ 219,000 $ 183,000
Mortgage banking income                 6,882,000 4,411,000 2,862,000
Other non interest income                 360,000 248,000 244,000
Total noninterest income                 7,242,000 4,659,000 3,106,000
Total non interest expenses                 4,688,000 4,918,000 3,881,000
INCOME BEFORE INCOME TAX EXPENSE                 2,754,000 (40,000) (592,000)
Income tax expense (benefit)                 964,000 (14,000) (207,000)
NET INCOME                 1,790,000 (26,000) (385,000)
Segment end of period total assets 17,453,000       9,348,000       17,453,000 9,348,000 11,593,000
Republic Processing Group                      
Segment information                      
Net interest income                 17,633,000 3,239,000 330,000
Provision for loan and lease losses                 10,548,000 2,331,000 (533,000)
Net refund transfer fees                 19,240,000 17,388,000 16,130,000
Program fees                 3,044,000 1,233,000 591,000
Other non interest income                 1,875,000 932,000 1,191,000
Total noninterest income                 24,159,000 19,553,000 17,912,000
Total non interest expenses                 13,917,000 12,140,000 11,667,000
INCOME BEFORE INCOME TAX EXPENSE                 17,327,000 8,321,000 7,108,000
Income tax expense (benefit)                 6,283,000 3,012,000 2,653,000
NET INCOME                 11,044,000 5,309,000 4,455,000
Segment end of period total assets $ 44,383,000       $ 25,001,000       $ 44,383,000 $ 25,001,000 $ 11,944,000