LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowance for Loan Losses and Recorded Investment By Portfolio Segment - (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Mar. 31, 2016	Dec. 31, 2015
Allowance for loan losses
Balance at the beginning of the period	$ 22,020	$ 23,250	$ 23,250
Provision charged to expense	500
Losses charged off	(2,442)	(1,356)
Recoveries	1,001	744
Balance at the end of the period	21,079	22,638	22,020
Allowance for loan losses
Ending Balance individually evaluated for impairment				$ 745	$ 1,429
Ending Balance collectively evaluated for impairment				20,334	20,591
Total ending allowance balance	22,020	23,250	23,250	21,079	22,020
Loans
Ending Balance individually evaluated for impairment				17,334	18,989
Ending Balance collectively evaluated for impairment				2,142,663	2,136,403
Total ending loan balance excluding accrued interest				2,159,997	2,155,392
Accrued interest				6,228	5,878
Allowance that includes a probability of default for subject loans	1,347		1,583
Commercial
Allowance for loan losses
Balance at the beginning of the period	6,511	2,977	2,977
Provision charged to expense	(110)	773
Losses charged off	(562)	(107)
Recoveries	150	32
Balance at the end of the period	5,989	3,675	6,511
Allowance for loan losses
Ending Balance individually evaluated for impairment				117	92
Ending Balance collectively evaluated for impairment				5,872	6,419
Total ending allowance balance	6,511	2,977	2,977	5,989	6,511
Loans
Ending Balance individually evaluated for impairment				764	812
Ending Balance collectively evaluated for impairment				439,673	444,852
Total ending loan balance excluding accrued interest				440,437	445,664
Commercial Real Estate
Allowance for loan losses
Balance at the beginning of the period	10,702	15,605	15,605
Provision charged to expense	(587)	(1,005)
Losses charged off	(503)	(58)
Recoveries	56	176
Balance at the end of the period	9,668	14,718	10,702
Allowance for loan losses
Ending Balance individually evaluated for impairment				460	1,166
Ending Balance collectively evaluated for impairment				9,208	9,536
Total ending allowance balance	10,702	15,605	15,605	9,668	10,702
Loans
Ending Balance individually evaluated for impairment				7,553	8,909
Ending Balance collectively evaluated for impairment				927,364	916,975
Total ending loan balance excluding accrued interest				934,917	925,884
Residential
Allowance for loan losses
Balance at the beginning of the period	3,859	3,501	3,501
Provision charged to expense	1,084	173
Losses charged off	(503)	(494)
Recoveries	113	148
Balance at the end of the period	4,553	3,328	3,859
Allowance for loan losses
Ending Balance individually evaluated for impairment				168	171
Ending Balance collectively evaluated for impairment				4,385	3,688
Total ending allowance balance	3,859	3,501	3,501	4,553	3,859
Loans
Ending Balance individually evaluated for impairment				8,897	9,155
Ending Balance collectively evaluated for impairment				717,529	717,918
Total ending loan balance excluding accrued interest				726,426	727,073
Consumer
Allowance for loan losses
Balance at the beginning of the period	948	1,167	1,167
Provision charged to expense	113	59
Losses charged off	(874)	(697)
Recoveries	682	388
Balance at the end of the period	869	917	948
Allowance for loan losses
Ending Balance collectively evaluated for impairment				869	948
Total ending allowance balance	$ 948	$ 1,167	$ 1,167	869	948
Loans
Ending Balance individually evaluated for impairment				120	113
Ending Balance collectively evaluated for impairment				58,097	56,658
Total ending loan balance excluding accrued interest				$ 58,217	$ 56,771