SEGMENT INFORMATION (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment Disclosure information
Number of operating segments | segment			4
Segment information
Net interest income	$ 39,398,000	$ 31,424,000	$ 114,409,000	$ 91,504,000
Provision for loan and lease losses	2,489,000	2,233,000	9,489,000	3,322,000
Net refund transfer fees	132,000	97,000	19,119,000	17,339,000
Mortgage banking income	3,081,000	972,000	5,902,000	3,549,000
Republic Processing Group program fees	979,000	474,000	1,942,000	871,000
Gain on call of security available for sale	0	0	0	88,000
Other non interest income	7,109,000	6,263,000	20,061,000	18,430,000
Total noninterest income	11,301,000	7,806,000	47,024,000	40,277,000
Total non interest expenses	33,534,000	28,238,000	97,941,000	86,477,000
INCOME BEFORE INCOME TAX EXPENSE	14,676,000	8,759,000	54,003,000	41,982,000
Income tax expense (benefit)	4,848,000	3,119,000	18,100,000	14,234,000
NET INCOME	9,828,000	5,640,000	35,903,000	27,748,000
Segment end of period total assets	$ 4,827,277,000	$ 4,035,977,000	$ 4,827,277,000	$ 4,035,977,000	$ 4,230,289,000
Net interest margin (as percent)	3.65%	3.31%	3.62%	3.26%
Core Banking Activities
Segment Disclosure information
Number of operating segments | segment			3
Segment information
Net interest income	$ 36,134,000	$ 30,987,000	$ 100,796,000	$ 89,903,000
Provision for loan and lease losses	477,000	1,100,000	2,253,000	2,192,000
Mortgage banking income	3,081,000	972,000	5,902,000	3,549,000
Gain on call of security available for sale				88,000
Other non interest income	6,960,000	6,199,000	19,606,000	17,536,000
Total noninterest income	10,041,000	7,171,000	25,508,000	21,173,000
Total non interest expenses	30,850,000	25,923,000	87,284,000	76,907,000
INCOME BEFORE INCOME TAX EXPENSE	14,848,000	11,135,000	36,767,000	31,977,000
Income tax expense (benefit)	4,910,000	4,040,000	11,847,000	10,632,000
NET INCOME	9,938,000	7,095,000	24,920,000	21,345,000
Segment end of period total assets	$ 4,784,877,000	$ 4,007,172,000	$ 4,784,877,000	$ 4,007,172,000
Net interest margin (as percent)	3.38%	3.29%	3.26%	3.26%
Traditional Banking
Segment information
Net interest income	$ 31,134,000	$ 27,612,000	$ 89,279,000	$ 80,369,000
Provision for loan and lease losses	289,000	1,338,000	1,567,000	2,007,000
Gain on call of security available for sale				88,000
Other non interest income	6,899,000	6,115,000	19,380,000	17,286,000
Total noninterest income	6,899,000	6,115,000	19,380,000	17,374,000
Total non interest expenses	28,939,000	24,109,000	81,551,000	71,351,000
INCOME BEFORE INCOME TAX EXPENSE	8,805,000	8,280,000	25,541,000	24,385,000
Income tax expense (benefit)	2,707,000	2,879,000	7,733,000	7,813,000
NET INCOME	6,098,000	5,401,000	17,808,000	16,572,000
Segment end of period total assets	$ 4,109,464,000	$ 3,600,230,000	$ 4,109,464,000	$ 3,600,230,000
Net interest margin (as percent)	3.35%	3.25%	3.22%	3.23%
Warehouse Lending
Segment information
Net interest income	$ 4,924,000	$ 3,308,000	$ 11,369,000	$ 9,354,000
Provision for loan and lease losses	188,000	(238,000)	686,000	185,000
Other non interest income	4,000	8,000	14,000	19,000
Total noninterest income	4,000	8,000	14,000	19,000
Total non interest expenses	727,000	663,000	2,157,000	1,846,000
INCOME BEFORE INCOME TAX EXPENSE	4,013,000	2,891,000	8,540,000	7,342,000
Income tax expense (benefit)	1,493,000	1,174,000	3,174,000	2,732,000
NET INCOME	2,520,000	1,717,000	5,366,000	4,610,000
Segment end of period total assets	$ 660,410,000	$ 393,110,000	$ 660,410,000	$ 393,110,000
Net interest margin (as percent)	3.63%	3.62%	3.64%	3.58%
Mortgage Banking
Segment information
Net interest income	$ 76,000	$ 67,000	$ 148,000	$ 180,000
Mortgage banking income	3,081,000	972,000	5,902,000	3,549,000
Other non interest income	57,000	76,000	212,000	231,000
Total noninterest income	3,138,000	1,048,000	6,114,000	3,780,000
Total non interest expenses	1,184,000	1,151,000	3,576,000	3,710,000
INCOME BEFORE INCOME TAX EXPENSE	2,030,000	(36,000)	2,686,000	250,000
Income tax expense (benefit)	710,000	(13,000)	940,000	87,000
NET INCOME	1,320,000	(23,000)	1,746,000	163,000
Segment end of period total assets	15,003,000	13,832,000	15,003,000	13,832,000
Republic Processing Group
Segment information
Net interest income	3,264,000	437,000	13,613,000	1,601,000
Provision for loan and lease losses	2,012,000	1,133,000	7,236,000	1,130,000
Net refund transfer fees	132,000	97,000	19,119,000	17,339,000
Republic Processing Group program fees	979,000	474,000	1,942,000	871,000
Other non interest income	149,000	64,000	455,000	894,000
Total noninterest income	1,260,000	635,000	21,516,000	19,104,000
Total non interest expenses	2,684,000	2,315,000	10,657,000	9,570,000
INCOME BEFORE INCOME TAX EXPENSE	(172,000)	(2,376,000)	17,236,000	10,005,000
Income tax expense (benefit)	(62,000)	(921,000)	6,253,000	3,602,000
NET INCOME	(110,000)	(1,455,000)	10,983,000	6,403,000
Segment end of period total assets	$ 42,400,000	$ 28,805,000	$ 42,400,000	$ 28,805,000