QUARTERLY FINANCIAL DATA (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Income Statement Data:
Interest income	$ 52,601	$ 51,195	$ 44,229	$ 42,368	$ 44,900	$ 43,186	$ 38,607	$ 37,873	$ 190,393	$ 164,566	$ 126,322
Interest expense	3,983	3,796	3,541	3,536	3,894	4,054	3,343	3,389	14,856	14,680	10,137
Net interest income	48,618	47,399	40,688	38,832	41,006	39,132	35,264	34,484	175,537	149,886	116,185
Provision for loan losses	553	986	2,656	1,069	888	1,669	1,365	1,726	5,264	5,648	11,486
Net interest income after provision for loan losses	48,065	46,413	38,032	37,763	40,118	37,463	33,899	32,758	170,273	144,238	104,699
Noninterest income	22,407	24,978	20,626	17,575	16,362	17,901	15,819	12,754	85,586	62,836	46,549
Noninterest expense	51,221	47,950	51,152	40,812	41,666	38,028	34,446	32,789	199,115	150,869	121,945
Acquisition related expenses	1,807	446	5,712	15	67	551	2,872	450
Income before income taxes	17,444	22,995	1,794	14,511	14,747	16,785	12,400	12,273	56,744	56,205	29,303
Income tax	3,296	7,368	486	4,747	4,167	5,122	4,270	3,923	15,897	17,482	9,285
Net income	14,148	15,627	1,308	9,764	10,580	11,663	8,130	8,350	40,847	38,723	20,018
Preferred stock dividends	0	0	0	0	0	0	0	286	0	286	1,738
Net income available to common stockholders	$ 14,148	$ 15,627	$ 1,308	$ 9,764	$ 10,580	$ 11,663	$ 8,130	$ 8,064	$ 40,847	$ 38,437	$ 18,280
Per Share Data:
Net income - basic	$ 0.44	$ 0.49	$ 0.04	$ 0.32	$ 0.40	$ 0.44	$ 0.32	$ 0.32	$ 1.29	$ 1.48	$ 0.76
Net income - diluted	0.43	0.48	0.04	0.32	0.39	0.43	0.32	0.32	1.27	1.46	0.75
Common Dividends (Cash)	0.05	0.05	0.05	0.05	0.05	0.05	0.05	0
Common Dividends (Stock)	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0.2	$ 0.15	$ 0