FAIR VALUE ACCOUNTING AND MEASUREMENT (Non-recurring Basis) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans individually evaluated for impairment	$ 58,747,000	$ 86,362,000	$ 58,747,000	$ 86,362,000
Allowance for credit losses, write-downs	4,912,000	11,489,000	20,255,000	43,061,000
Allowance individually evaluated for impairment	5,363,000	8,985,000	5,363,000	8,985,000
Loans collectively evaluated for impairment	3,154,776,000	3,138,884,000	3,154,776,000	3,138,884,000
Allowance collectively evaluated for impairment	73,420,000	77,143,000	73,420,000	77,143,000
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classifed loans	146,000,000		146,000,000
Impaired financing receivable	101,000,000		101,000,000
Loans individually evaluated for impairment	59,000,000		59,000,000
Individually evaluated for impairment, carrying value	66,000,000		66,000,000
Allowance for credit losses, write-downs			7,000,000
Allowance individually evaluated for impairment	5,000,000		5,000,000
Loans collectively evaluated for impairment	42,000,000		42,000,000
Collectively evaluated for impairment, troubled debt restructuring	26,000,000		26,000,000
Allowance collectively evaluated for impairment	3,000,000		3,000,000
Impairment of real estate owned	$ 1,300,000	$ 4,600,000	$ 4,400,000	$ 12,400,000