FAIR VALUE ACCOUNTING AND MEASUREMENT (Non-recurring Basis) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans individually evaluated for impairment	$ 72,632,000	$ 72,390,000
Allowance for credit losses, write-downs	2,691,000	7,729,000
Allowance individually evaluated for impairment	7,531,000	4,550,000
Loans collectively evaluated for impairment	3,167,689,000	3,157,272,000
Allowance collectively evaluated for impairment	69,597,000	76,994,000
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classifed loans	118,000,000
Impaired financing receivable	88,000,000
Loans individually evaluated for impairment	73,000,000
Individually evaluated for impairment, carrying value	76,000,000
Allowance for credit losses, write-downs	3,000,000
Allowance individually evaluated for impairment	8,000,000
Loans collectively evaluated for impairment	15,000,000
Allowance collectively evaluated for impairment	888,000
Impairment of real estate owned	$ 73,000	$ 1,600,000