ALLOWANCE FOR LOAN AND LEASE LOSSES - Changes in the Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Allowance for loan and lease losses:
Balance at beginning of period	$ 56,326	$ 53,732	$ 57,961	$ 53,398
Provision for loan and lease losses	467	4,037	834	5,692
Loans charged-off	(4,498)	(2,702)	(7,248)	(5,144)
Recoveries	2,578	1,641	3,326	2,762
Total net charge-offs	(1,920)	(1,061)	(3,922)	(2,382)
Balance at end of period	54,873	56,708	54,873	56,708
Ending allowance on loans individually evaluated for impairment					$ 2,729	$ 1,324
Ending allowance on loans collectively evaluated for impairment					52,144	56,637
Ending allowance for loan and lease losses	56,326	53,732	57,961	53,398	54,873	57,961
Loans and Leases:
Ending balance of loans individually evaluated for impairment					56,706	47,970
Ending balance of loans collectively evaluated for impairment					5,817,059	5,709,512
Loans and Leases Receivable, Net of Deferred Income					5,873,765	5,757,482
Commercial
Allowance for loan and lease losses:
Balance at beginning of period	17,148	18,170	19,225	16,995
Provision for loan and lease losses	3,537	2,572	2,941	4,004
Loans charged-off	(3,065)	(265)	(4,808)	(744)
Recoveries	693	420	955	642
Total net charge-offs	(2,372)	155	(3,853)	(102)
Balance at end of period	18,313	20,897	18,313	20,897
Ending allowance on loans individually evaluated for impairment					2,443	550
Ending allowance on loans collectively evaluated for impairment					15,870	18,675
Ending allowance for loan and lease losses	17,148	18,170	19,225	16,995	18,313	19,225
Loans and Leases:
Ending balance of loans individually evaluated for impairment					18,799	13,203
Ending balance of loans collectively evaluated for impairment					1,805,790	1,768,745
Loans and Leases Receivable, Net of Deferred Income					1,824,589	1,781,948
Lease financing
Allowance for loan and lease losses:
Balance at beginning of period	616	866	716	821
Provision for loan and lease losses	(67)	1,014	(167)	1,059
Loans charged-off	0	0	0	0
Recoveries	1	1	1	1
Total net charge-offs	1	1	1	1
Balance at end of period	550	1,881	550	1,881
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					550	716
Ending allowance for loan and lease losses	616	866	716	821	550	716
Loans and Leases:
Ending balance of loans individually evaluated for impairment					94	195
Ending balance of loans collectively evaluated for impairment					88,058	92,913
Loans and Leases Receivable, Net of Deferred Income					88,152	93,108
Construction real estate
Allowance for loan and lease losses:
Balance at beginning of period	3,607	2,272	3,282	1,810
Provision for loan and lease losses	(280)	447	45	886
Loans charged-off	0	(28)	0	(31)
Recoveries	89	202	89	228
Total net charge-offs	89	174	89	197
Balance at end of period	3,416	2,893	3,416	2,893
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					3,416	3,282
Ending allowance for loan and lease losses	3,607	2,272	3,282	1,810	3,416	3,282
Loans and Leases:
Ending balance of loans individually evaluated for impairment					1,075	0
Ending balance of loans collectively evaluated for impairment					442,037	399,434
Loans and Leases Receivable, Net of Deferred Income					443,112	399,434
Commercial real estate
Allowance for loan and lease losses:
Balance at beginning of period	23,745	22,416	26,540	23,656
Provision for loan and lease losses	(2,941)	1,283	(5,507)	863
Loans charged-off	(485)	(1,596)	(970)	(2,858)
Recoveries	1,398	681	1,654	1,123
Total net charge-offs	913	(915)	684	(1,735)
Balance at end of period	21,717	22,784	21,717	22,784
Ending allowance on loans individually evaluated for impairment					124	593
Ending allowance on loans collectively evaluated for impairment					21,593	25,947
Ending allowance for loan and lease losses	23,745	22,416	26,540	23,656	21,717	26,540
Loans and Leases:
Ending balance of loans individually evaluated for impairment					24,081	20,460
Ending balance of loans collectively evaluated for impairment					2,447,574	2,407,117
Loans and Leases Receivable, Net of Deferred Income					2,471,655	2,427,577
Residential real estate
Allowance for loan and lease losses:
Balance at beginning of period	5,485	4,040	3,208	4,014
Provision for loan and lease losses	(305)	(801)	2,024	(793)
Loans charged-off	(223)	(28)	(284)	(73)
Recoveries	59	81	68	144
Total net charge-offs	(164)	53	(216)	71
Balance at end of period	5,016	3,292	5,016	3,292
Ending allowance on loans individually evaluated for impairment					160	179
Ending allowance on loans collectively evaluated for impairment					4,856	3,029
Ending allowance for loan and lease losses	5,485	4,040	3,208	4,014	5,016	3,208
Loans and Leases:
Ending balance of loans individually evaluated for impairment					8,628	9,601
Ending balance of loans collectively evaluated for impairment					481,770	491,379
Loans and Leases Receivable, Net of Deferred Income					490,398	500,980
Home equity
Allowance for loan and lease losses:
Balance at beginning of period	3,774	3,976	3,043	3,943
Provision for loan and lease losses	526	(707)	1,331	(522)
Loans charged-off	(384)	(398)	(564)	(738)
Recoveries	222	131	328	319
Total net charge-offs	(162)	(267)	(236)	(419)
Balance at end of period	4,138	3,002	4,138	3,002
Ending allowance on loans individually evaluated for impairment					2	2
Ending allowance on loans collectively evaluated for impairment					4,136	3,041
Ending allowance for loan and lease losses	3,774	3,976	3,043	3,943	4,138	3,043
Loans and Leases:
Ending balance of loans individually evaluated for impairment					3,704	4,074
Ending balance of loans collectively evaluated for impairment					460,362	456,314
Loans and Leases Receivable, Net of Deferred Income					464,066	460,388
Installment
Allowance for loan and lease losses:
Balance at beginning of period	419	354	388	386
Provision for loan and lease losses	19	(3)	28	(61)
Loans charged-off	(126)	(30)	(175)	(103)
Recoveries	43	62	114	161
Total net charge-offs	(83)	32	(61)	58
Balance at end of period	355	383	355	383
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					355	388
Ending allowance for loan and lease losses	419	354	388	386	355	388
Loans and Leases:
Ending balance of loans individually evaluated for impairment					325	437
Ending balance of loans collectively evaluated for impairment					47,329	50,202
Loans and Leases Receivable, Net of Deferred Income					47,654	50,639
Credit card
Allowance for loan and lease losses:
Balance at beginning of period	1,532	1,638	1,559	1,773
Provision for loan and lease losses	(22)	232	139	256
Loans charged-off	(215)	(357)	(447)	(597)
Recoveries	73	63	117	144
Total net charge-offs	(142)	(294)	(330)	(453)
Balance at end of period	1,368	1,576	1,368	1,576
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					1,368	1,559
Ending allowance for loan and lease losses	$ 1,532	$ 1,638	$ 1,559	$ 1,773	1,368	1,559
Loans and Leases:
Ending balance of loans individually evaluated for impairment					0	0
Ending balance of loans collectively evaluated for impairment					44,139	43,408
Loans and Leases Receivable, Net of Deferred Income					$ 44,139	$ 43,408