ALLOWANCE FOR LOAN AND LEASE LOSSES - Changes in the Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Allowance for loan and lease losses:
Balance at beginning of period	$ 54,873	$ 56,708	$ 57,961	$ 53,398
Provision for loan and lease losses	2,953	1,687	3,787	7,379
Loans charged-off	(4,499)	(2,550)	(11,747)	(7,694)
Recoveries	1,207	1,773	4,533	4,535
Total net charge-offs	(3,292)	(777)	(7,214)	(3,159)
Balance at end of period	54,534	57,618	54,534	57,618
Ending allowance on loans individually evaluated for impairment					$ 385	$ 1,324
Ending allowance on loans collectively evaluated for impairment					54,149	56,637
Ending allowance for loan and lease losses	54,873	56,708	57,961	53,398	54,534	57,961
Loans and Leases:
Ending balance of loans individually evaluated for impairment					49,810	47,970
Ending balance of loans collectively evaluated for impairment					5,927,227	5,709,512
Loans and Leases Receivable, Net of Deferred Income					5,977,037	5,757,482
Commercial
Allowance for loan and lease losses:
Balance at beginning of period	18,313	20,897	19,225	16,995
Provision for loan and lease losses	3,024	(720)	5,965	3,284
Loans charged-off	(4,122)	(296)	(8,930)	(1,040)
Recoveries	325	327	1,280	969
Total net charge-offs	(3,797)	31	(7,650)	(71)
Balance at end of period	17,540	20,208	17,540	20,208
Ending allowance on loans individually evaluated for impairment					179	550
Ending allowance on loans collectively evaluated for impairment					17,361	18,675
Ending allowance for loan and lease losses	18,313	20,897	19,225	16,995	17,540	19,225
Loans and Leases:
Ending balance of loans individually evaluated for impairment					12,325	13,203
Ending balance of loans collectively evaluated for impairment					1,873,768	1,768,745
Loans and Leases Receivable, Net of Deferred Income					1,886,093	1,781,948
Lease financing
Allowance for loan and lease losses:
Balance at beginning of period	550	1,881	716	821
Provision for loan and lease losses	507	(1,011)	340	48
Loans charged-off	0	0	0	0
Recoveries	0	0	1	1
Total net charge-offs	0	0	1	1
Balance at end of period	1,057	870	1,057	870
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					1,057	716
Ending allowance for loan and lease losses	550	1,881	716	821	1,057	716
Loans and Leases:
Ending balance of loans individually evaluated for impairment					87	195
Ending balance of loans collectively evaluated for impairment					85,927	92,913
Loans and Leases Receivable, Net of Deferred Income					86,014	93,108
Construction real estate
Allowance for loan and lease losses:
Balance at beginning of period	3,416	2,893	3,282	1,810
Provision for loan and lease losses	(178)	232	(133)	1,118
Loans charged-off	0	(64)	0	(95)
Recoveries	0	6	89	234
Total net charge-offs	0	(58)	89	139
Balance at end of period	3,238	3,067	3,238	3,067
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					3,238	3,282
Ending allowance for loan and lease losses	3,416	2,893	3,282	1,810	3,238	3,282
Loans and Leases:
Ending balance of loans individually evaluated for impairment					824	0
Ending balance of loans collectively evaluated for impairment					420,117	399,434
Loans and Leases Receivable, Net of Deferred Income					420,941	399,434
Commercial real estate
Allowance for loan and lease losses:
Balance at beginning of period	21,717	22,784	26,540	23,656
Provision for loan and lease losses	(1,003)	2,628	(6,510)	3,491
Loans charged-off	(58)	(1,135)	(1,028)	(3,993)
Recoveries	585	997	2,239	2,120
Total net charge-offs	527	(138)	1,211	(1,873)
Balance at end of period	21,241	25,274	21,241	25,274
Ending allowance on loans individually evaluated for impairment					44	593
Ending allowance on loans collectively evaluated for impairment					21,197	25,947
Ending allowance for loan and lease losses	21,717	22,784	26,540	23,656	21,241	26,540
Loans and Leases:
Ending balance of loans individually evaluated for impairment					23,597	20,460
Ending balance of loans collectively evaluated for impairment					2,499,790	2,407,117
Loans and Leases Receivable, Net of Deferred Income					2,523,387	2,427,577
Residential real estate
Allowance for loan and lease losses:
Balance at beginning of period	5,016	3,292	3,208	4,014
Provision for loan and lease losses	(243)	(13)	1,781	(806)
Loans charged-off	(23)	(90)	(307)	(163)
Recoveries	70	38	138	182
Total net charge-offs	47	(52)	(169)	19
Balance at end of period	4,820	3,227	4,820	3,227
Ending allowance on loans individually evaluated for impairment					160	179
Ending allowance on loans collectively evaluated for impairment					4,660	3,029
Ending allowance for loan and lease losses	5,016	3,292	3,208	4,014	4,820	3,208
Loans and Leases:
Ending balance of loans individually evaluated for impairment					8,644	9,601
Ending balance of loans collectively evaluated for impairment					469,320	491,379
Loans and Leases Receivable, Net of Deferred Income					477,964	500,980
Home equity
Allowance for loan and lease losses:
Balance at beginning of period	4,138	3,002	3,043	3,943
Provision for loan and lease losses	819	275	2,150	(247)
Loans charged-off	(71)	(475)	(635)	(1,213)
Recoveries	110	257	438	576
Total net charge-offs	39	(218)	(197)	(637)
Balance at end of period	4,996	3,059	4,996	3,059
Ending allowance on loans individually evaluated for impairment					2	2
Ending allowance on loans collectively evaluated for impairment					4,994	3,041
Ending allowance for loan and lease losses	4,138	3,002	3,043	3,943	4,996	3,043
Loans and Leases:
Ending balance of loans individually evaluated for impairment					4,079	4,074
Ending balance of loans collectively evaluated for impairment					490,263	456,314
Loans and Leases Receivable, Net of Deferred Income					494,342	460,388
Installment
Allowance for loan and lease losses:
Balance at beginning of period	355	383	388	386
Provision for loan and lease losses	(80)	168	(52)	107
Loans charged-off	(24)	(223)	(199)	(326)
Recoveries	74	56	188	217
Total net charge-offs	50	(167)	(11)	(109)
Balance at end of period	325	384	325	384
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					325	388
Ending allowance for loan and lease losses	355	383	388	386	325	388
Loans and Leases:
Ending balance of loans individually evaluated for impairment					254	437
Ending balance of loans collectively evaluated for impairment					43,396	50,202
Loans and Leases Receivable, Net of Deferred Income					43,650	50,639
Credit card
Allowance for loan and lease losses:
Balance at beginning of period	1,368	1,576	1,559	1,773
Provision for loan and lease losses	107	128	246	384
Loans charged-off	(201)	(267)	(648)	(864)
Recoveries	43	92	160	236
Total net charge-offs	(158)	(175)	(488)	(628)
Balance at end of period	1,317	1,529	1,317	1,529
Ending allowance on loans individually evaluated for impairment					0	0
Ending allowance on loans collectively evaluated for impairment					1,317	1,559
Ending allowance for loan and lease losses	$ 1,368	$ 1,576	$ 1,559	$ 1,773	1,317	1,559
Loans and Leases:
Ending balance of loans individually evaluated for impairment					0	0
Ending balance of loans collectively evaluated for impairment					44,646	43,408
Loans and Leases Receivable, Net of Deferred Income					$ 44,646	$ 43,408