QUARTERLY DATA (UNAUDITED) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest and dividend income	$ 54,016	$ 52,056	$ 51,175	$ 49,795	$ 48,659	$ 54,504	$ 49,697	$ 50,881	$ 207,042	$ 203,741	$ 175,939
Interest expense	7,369	7,107	6,846	7,029	8,817	8,635	8,593	8,944	28,351	34,989	32,551
Net interest income	46,647	44,949	44,329	42,766	39,842	45,869	41,104	41,937	178,691	168,752	143,388
Non-interest income	14,200	14,641	14,506	4,423	15,714	12,114	15,606	14,798	47,770	58,232	54,056
Total net revenue	60,847	59,590	58,835	47,189	55,556	57,983	56,710	56,735	226,461	226,984	197,444
Provision for loan losses	3,898	3,685	3,989	3,396	3,100	3,178	2,700	2,400	14,968	11,378	9,590
Non-interest expense	41,676	39,687	39,263	45,360	37,157	42,784	37,935	39,483	165,986	157,359	140,806
Income before income taxes	15,273	16,218	15,583	(1,567)	15,299	12,021	16,075	14,852	45,507	58,247	47,048
Income tax expense	3,875	4,230	4,119	(461)	4,762	3,917	4,038	4,387	11,763	17,104	13,223
Net income from continuing operations	11,398	11,988	11,464	(1,106)	10,537	8,104	12,037	10,465	33,744	41,143	33,825
Loss from discontinued operations, net of tax											(637)
Net income	$ 11,398	$ 11,988	$ 11,464	$ (1,106)	$ 10,537	$ 8,104	$ 12,037	$ 10,465	$ 33,744	$ 41,143	$ 33,188
Basic earnings per share:
Continuing Operations (in dollars per share)	$ 0.46	$ 0.48	$ 0.46	$ (0.04)	$ 0.43	$ 0.33	$ 0.49	$ 0.42	$ 1.36	$ 1.66	$ 1.52
Discontinued operations (in dollars per share)											$ (0.03)
Total basic earning per share (in dollars per share)	$ 0.46	$ 0.48	$ 0.46	$ (0.04)	$ 0.43	$ 0.33	$ 0.49	$ 0.42	$ 1.36	$ 1.66	$ 1.49
Diluted earnings per share:
Continuing Operations (in dollars per share)	$ 0.46	$ 0.48	$ 0.46	$ (0.04)	$ 0.42	$ 0.33	$ 0.48	$ 0.42	$ 1.36	$ 1.65	$ 1.52
Discontinued operations (in dollars per share)											$ (0.03)
Total diluted earnings per share (in dollars per share)	$ 0.46	$ 0.48	$ 0.46	$ (0.04)	$ 0.42	$ 0.33	$ 0.48	$ 0.42	$ 1.36	$ 1.65	$ 1.49
Weighted average common shares outstanding:
Basic (in shares)	24,758	24,747	24,715	24,698	24,701	24,748	24,779	24,948	24,730	24,802	22,201
Diluted (in shares)	24,912	24,861	24,809	24,698	24,857	24,873	24,956	25,143	24,854	24,965	22,329