SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Disclosure information
Number of reportable segments | segment	5
Segment information
Net interest income	$ 67,665	$ 56,438
Provision for loan and lease losses	17,255	12,351
Net refund transfer fees	16,352	15,382
Mortgage banking income	1,020	1,160
Program fees	1,696	1,091
Other noninterest income	8,477	7,290
Total noninterest income	27,545	24,923
Total noninterest expenses	43,045	38,939
INCOME BEFORE INCOME TAX EXPENSE	34,910	30,071
Income tax expense (benefit)	7,441	10,054
NET INCOME	27,469	20,017
Segment end of period assets	$ 5,078,334	$ 4,664,792	$ 5,085,362
Net interest margin (as percent)	5.50%	4.99%
Net-revenue concentration (as percent)	100.00%	100.00%
Core Banking Activities
Segment Disclosure information
Number of reportable segments | segment	3
Segment information
Net interest income	$ 41,851	$ 36,628
Provision for loan and lease losses	960	241
Mortgage banking income	1,020	1,160
Other noninterest income	7,048	6,537
Total noninterest income	8,068	7,697
Total noninterest expenses	35,435	32,079
INCOME BEFORE INCOME TAX EXPENSE	13,524	12,005
Income tax expense (benefit)	2,383	3,498
NET INCOME	11,141	8,507
Segment end of period assets	$ 4,888,750	$ 4,525,380
Net interest margin (as percent)	3.55%	3.33%
Net-revenue concentration (as percent)	52.00%	55.00%
Traditional Banking
Segment information
Net interest income	$ 38,188	$ 32,661
Provision for loan and lease losses	939	467
Other noninterest income	7,002	6,519
Total noninterest income	7,002	6,519
Total noninterest expenses	33,392	30,088
INCOME BEFORE INCOME TAX EXPENSE	10,859	8,625
Income tax expense (benefit)	1,772	2,262
NET INCOME	9,087	6,363
Segment end of period assets	$ 4,344,341	$ 4,017,173
Net interest margin (as percent)	3.59%	3.30%
Net-revenue concentration (as percent)	47.00%	48.00%
Warehouse Lending
Segment information
Net interest income	$ 3,591	$ 3,900
Provision for loan and lease losses	21	(226)
Other noninterest income	8	6
Total noninterest income	8	6
Total noninterest expenses	839	777
INCOME BEFORE INCOME TAX EXPENSE	2,739	3,355
Income tax expense (benefit)	627	1,227
NET INCOME	2,112	2,128
Segment end of period assets	$ 534,545	$ 493,127
Net interest margin (as percent)	3.21%	3.57%
Net-revenue concentration (as percent)	4.00%	5.00%
Mortgage Banking
Segment information
Net interest income	$ 72	$ 67
Mortgage banking income	1,020	1,160
Other noninterest income	38	12
Total noninterest income	1,058	1,172
Total noninterest expenses	1,204	1,214
INCOME BEFORE INCOME TAX EXPENSE	(74)	25
Income tax expense (benefit)	(16)	9
NET INCOME	(58)	16
Segment end of period assets	$ 9,864	$ 15,080
Net-revenue concentration (as percent)	1.00%	2.00%
Republic Processing Group
Segment Disclosure information
Number of reportable segments | segment	2
Segment information
Net interest income	$ 25,814	$ 19,810
Provision for loan and lease losses	16,295	12,110
Net refund transfer fees	16,352	15,382
Program fees	1,696	1,091
Other noninterest income	1,429	753
Total noninterest income	19,477	17,226
Total noninterest expenses	7,610	6,860
INCOME BEFORE INCOME TAX EXPENSE	21,386	18,066
Income tax expense (benefit)	5,058	6,556
NET INCOME	16,328	11,510
Segment end of period assets	$ 189,584	$ 139,412
Net-revenue concentration (as percent)	48.00%	45.00%
Tax Refund Solutions
Segment information
Net interest income	$ 18,686	$ 14,962
Provision for loan and lease losses	13,389	8,341
Net refund transfer fees	16,352	15,382
Program fees	59	(17)
Other noninterest income	1,110	68
Total noninterest income	17,521	15,433
Total noninterest expenses	6,525	6,069
INCOME BEFORE INCOME TAX EXPENSE	16,293	15,985
Income tax expense (benefit)	3,854	5,801
NET INCOME	12,439	10,184
Segment end of period assets	$ 129,395	$ 108,858
Net-revenue concentration (as percent)	38.00%	37.00%
Republic Credit Solutions
Segment information
Net interest income	$ 7,128	$ 4,848
Provision for loan and lease losses	2,906	3,769
Program fees	1,637	1,108
Other noninterest income	319	685
Total noninterest income	1,956	1,793
Total noninterest expenses	1,085	791
INCOME BEFORE INCOME TAX EXPENSE	5,093	2,081
Income tax expense (benefit)	1,204	755
NET INCOME	3,889	1,326
Segment end of period assets	$ 60,189	$ 30,554
Net-revenue concentration (as percent)	10.00%	8.00%