LOANS, Loan Summary (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Loans receivable, net [Abstract]
Typical contract term of consumer mortgages, minimum	10 years
Typical contract term of consumer mortgages, maximum	30 years
Typical contract term of home equity loans, maximum	30 years
Gross loans, including deferred origination costs	$ 4,163,911,000	$ 4,236,206,000
Allowance for loan losses	(45,005,000)	(45,341,000)	(44,197,000)	(44,319,000)
Net loans	4,118,906,000	4,190,865,000
Credit impaired acquired loans, outstanding balance	5,900,000	6,100,000
Accretable discount related to credit impaired acquired loans [Roll forward]
Beginning Balance	705,000
Accretion recognized, year-to-date	(151,000)
Net reclassification to accretable from nonaccretable	28,000
Ending Balance	582,000
Consumer Mortgage [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	1,605,019,000	1,613,384,000
Allowance for loan losses	(10,233,000)	(10,286,000)	(9,281,000)	(8,994,000)
Business Lending [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	1,239,529,000	1,262,484,000
Allowance for loan losses	(15,405,000)	(15,787,000)	(17,046,000)	(17,507,000)
Consumer Indirect [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	804,300,000	833,968,000
Allowance for loan losses	(11,246,000)	(11,544,000)	(10,586,000)	(10,248,000)
Consumer Direct [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	176,084,000	184,028,000
Allowance for loan losses	(2,879,000)	(3,083,000)	(3,087,000)	(3,181,000)
Home Equity [Member]
Loans receivable, net [Abstract]
Gross loans, including deferred origination costs	338,979,000	342,342,000
Allowance for loan losses	$ (2,663,000)	$ (2,701,000)	$ (1,818,000)	$ (1,830,000)