ALLOWANCE FOR LOAN AND LEASE LOSSES - Changes in the Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Allowance for loan and lease losses:
Balance at beginning of period	$ 53,398	$ 52,858
Provision for loan and lease losses	1,655	2,060
Gross charge-offs	2,442	5,044
Recoveries	1,121	3,202
Total net charge-offs	1,321	1,842
Balance at end of period	53,732	53,076
Ending allowance on loans individually evaluated for impairment	1,401		$ 1,573
Ending allowance on loans collectively evaluated for impairment	52,331		51,825
Loans and Leases:
Ending balance of loans individually evaluated for impairment	52,134		56,873
Ending balance of loans collectively evaluated for impairment	5,452,475		5,331,887
Loans and Leases Receivable, Net of Deferred Income	5,504,609		5,388,760
Non Covered Loans
Allowance for loan and lease losses:
Balance at beginning of period		52,858
Commercial
Allowance for loan and lease losses:
Balance at beginning of period	16,995	13,870
Provision for loan and lease losses	1,432	1,059
Gross charge-offs	479	1,568
Recoveries	222	2,183
Total net charge-offs	257	(615)
Balance at end of period	18,170	15,544
Ending allowance on loans individually evaluated for impairment	400		357
Ending allowance on loans collectively evaluated for impairment	17,770		16,638
Loans and Leases:
Ending balance of loans individually evaluated for impairment	14,485		17,411
Ending balance of loans collectively evaluated for impairment	1,730,247		1,645,691
Loans and Leases Receivable, Net of Deferred Income	1,744,732		1,663,102
Real estate - construction
Allowance for loan and lease losses:
Balance at beginning of period	1,810	1,045
Provision for loan and lease losses	439	147
Gross charge-offs	3	0
Recoveries	26	45
Total net charge-offs	(23)	(45)
Balance at end of period	2,272	1,237
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	2,272		1,810
Loans and Leases:
Ending balance of loans individually evaluated for impairment	0		0
Ending balance of loans collectively evaluated for impairment	341,453		311,712
Loans and Leases Receivable, Net of Deferred Income	341,453		311,712
Real estate - commercial
Allowance for loan and lease losses:
Balance at beginning of period	23,656	27,086
Provision for loan and lease losses	(420)	112
Gross charge-offs	1,262	1,870
Recoveries	442	491
Total net charge-offs	820	1,379
Balance at end of period	22,416	25,819
Ending allowance on loans individually evaluated for impairment	763		979
Ending allowance on loans collectively evaluated for impairment	21,653		22,677
Loans and Leases:
Ending balance of loans individually evaluated for impairment	22,977		24,652
Ending balance of loans collectively evaluated for impairment	2,238,880		2,233,645
Loans and Leases Receivable, Net of Deferred Income	2,261,857		2,258,297
Real estate - residential
Allowance for loan and lease losses:
Balance at beginning of period	4,014	3,753
Provision for loan and lease losses	8	70
Gross charge-offs	45	404
Recoveries	63	64
Total net charge-offs	(18)	340
Balance at end of period	4,040	3,483
Ending allowance on loans individually evaluated for impairment	236		235
Ending allowance on loans collectively evaluated for impairment	3,804		3,779
Loans and Leases:
Ending balance of loans individually evaluated for impairment	8,663		8,994
Ending balance of loans collectively evaluated for impairment	499,849		503,317
Loans and Leases Receivable, Net of Deferred Income	508,512		512,311
Installment
Allowance for loan and lease losses:
Balance at beginning of period	386	407
Provision for loan and lease losses	(58)	61
Gross charge-offs	73	167
Recoveries	99	86
Total net charge-offs	(26)	81
Balance at end of period	354	387
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	354		386
Loans and Leases:
Ending balance of loans individually evaluated for impairment	219		253
Ending balance of loans collectively evaluated for impairment	41,408		41,253
Loans and Leases Receivable, Net of Deferred Income	41,627		41,506
Home equity
Allowance for loan and lease losses:
Balance at beginning of period	3,943	4,260
Provision for loan and lease losses	185	472
Gross charge-offs	340	741
Recoveries	188	288
Total net charge-offs	152	453
Balance at end of period	3,976	4,279
Ending allowance on loans individually evaluated for impairment	2		2
Ending allowance on loans collectively evaluated for impairment	3,974		3,941
Loans and Leases:
Ending balance of loans individually evaluated for impairment	5,669		5,441
Ending balance of loans collectively evaluated for impairment	460,341		461,188
Loans and Leases Receivable, Net of Deferred Income	466,010		466,629
All other
Allowance for loan and lease losses:
Balance at beginning of period	2,594	2,437
Provision for loan and lease losses	69	139
Gross charge-offs	240	294
Recoveries	81	45
Total net charge-offs	159	249
Balance at end of period	2,504	$ 2,327
Ending allowance on loans individually evaluated for impairment	0		0
Ending allowance on loans collectively evaluated for impairment	2,504		2,594
Loans and Leases:
Ending balance of loans individually evaluated for impairment	121		122
Ending balance of loans collectively evaluated for impairment	140,297		135,081
Loans and Leases Receivable, Net of Deferred Income	$ 140,418		$ 135,203