LOANS, ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 48,260		$ 46,255		$ 42,361
Charge-offs	(16,592)		(11,341)		(16,187)
Recoveries	2,110		1,864		1,426
Provision	18,056		11,482		18,655
Ending balance	51,834		48,260		46,255
Ending balance: individually evaluated for impairment	3,420		2,682		2,547
Ending balance: collectively evaluated for impairment	48,414		45,578		43,708
Financing receivables
Total loans	4,519,011	[1]	3,794,390	[1]	3,555,679	[1]
Ending balance: individually evaluated for impairment	66,659		61,701		47,386
Ending balance: collectively evaluated for impairment	4,452,352		3,732,689		3,508,293
Commercial and Industrial [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,682		10,423		7,545
Charge-offs	(6,191)		(2,888)		(5,170)
Recoveries	963		420		361
Provision	7,007		3,727		7,687
Ending balance	13,461		11,682		10,423
Ending balance: individually evaluated for impairment	1,084		562		511
Ending balance: collectively evaluated for impairment	12,377		11,120		9,912
Financing receivables
Total loans	687,511		575,716		502,952
Ending balance: individually evaluated for impairment	8,575		5,608		3,823
Ending balance: collectively evaluated for impairment	678,936		570,108		499,129
Commercial Real Estate [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	23,514		21,939		19,451
Charge-offs	(4,348)		(2,631)		(3,448)
Recoveries	188		97		1
Provision	3,244		4,109		5,935
Ending balance	22,598		23,514		21,939
Ending balance: individually evaluated for impairment	516		457		411
Ending balance: collectively evaluated for impairment	22,082		23,057		21,528
Financing receivables
Total loans	2,122,153		1,847,654		1,717,118
Ending balance: individually evaluated for impairment	33,868		37,476		26,665
Ending balance: collectively evaluated for impairment	2,088,285		1,810,178		1,690,453
Commercial Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,076		2,145		2,457
Charge-offs			(769)		(1,716)
Recoveries			500
Provision	735		200		1,404
Ending balance	2,811		2,076		2,145
Ending balance: individually evaluated for impairment					151
Ending balance: collectively evaluated for impairment	2,811		2,076		1,994
Financing receivables
Total loans	188,768		128,904		129,421
Ending balance: individually evaluated for impairment			843		1,999
Ending balance: collectively evaluated for impairment	188,768		128,061		127,422
Small Business [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,896		3,740		3,372
Charge-offs	(616)		(1,190)		(2,279)
Recoveries	134		160		217
Provision	110		(814)		2,430
Ending balance	1,524		1,896		3,740
Ending balance: individually evaluated for impairment	353		148		221
Ending balance: collectively evaluated for impairment	1,171		1,748		3,519
Financing receivables
Total loans	78,594		78,509		80,026
Ending balance: individually evaluated for impairment	2,279		2,326		2,494
Ending balance: collectively evaluated for impairment	76,315		76,183		77,532
Residential Real Estate [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,113		2,915		2,840
Charge-offs	(1,094)		(559)		(557)
Recoveries	151				59
Provision	760		757		573
Ending balance	2,930		3,113		2,915
Ending balance: individually evaluated for impairment	1,302		1,245		991
Ending balance: collectively evaluated for impairment	1,628		1,868		1,924
Financing receivables
Total loans	612,881		426,201		478,111
Ending balance: individually evaluated for impairment	15,373		12,984		9,963
Ending balance: collectively evaluated for impairment	597,508		413,217		468,148
Home Equity [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,597		3,369		3,945
Charge-offs	(3,178)		(1,626)		(939)
Recoveries	93		52		131
Provision	6,191		2,802		232
Ending balance	7,703		4,597		3,369
Ending balance: individually evaluated for impairment	35		31		17
Ending balance: collectively evaluated for impairment	7,668		4,566		3,352
Financing receivables
Total loans	802,149		696,063		579,278
Ending balance: individually evaluated for impairment	4,435		326		428
Ending balance: collectively evaluated for impairment	797,714		695,737		578,850
Consumer Other [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,382		1,724		2,751
Charge-offs	(1,165)		(1,678)		(2,078)
Recoveries	581		635		657
Provision	9		701		394
Ending balance	807		1,382		1,724
Ending balance: individually evaluated for impairment	130		239		245
Ending balance: collectively evaluated for impairment	677		1,143		1,479
Financing receivables
Total loans	26,955		41,343		68,773
Ending balance: individually evaluated for impairment	2,129		2,138		2,014
Ending balance: collectively evaluated for impairment	$ 24,826		$ 39,205		$ 66,759

[1] The amount of deferred fees included in the ending balance was $3.1 million, $2.9 million, and $2.8 million at December 31, 2012, 2011, and 2010, respectively.