FAIR VALUE OF FINANCIAL INSTRUMENTS (Non-recurring Basis) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans individually evaluated for valuation adjustments	$ 63,123,000	$ 81,447,000
Impaired loans individually evaluated for valuation adjustments, write-downs	25,887,000	52,906,000
Impaired loans individually evaluated for valuation adjustments, specific reserves	5,725,000	7,034,000
Impaired loans collectively evaluated for valuation adjustments	3,172,591,000	3,214,891,000
Impaired loans collectively evaluated for valuation adjustments, allowances	71,766,000	75,878,000
Mortgage servicing rights impairment	400,000
Servicing Contracts for Third Parties [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans serviced for others	1,031,000,000	773,000,000
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classifed loans	131,000,000
Impaired classified loans	92,000,000
Impaired loans individually evaluated for valuation adjustments	63,000,000
Impaired loans individually evaluated for valuation adjustments, carrying value	66,000,000
Impaired loans individually evaluated for valuation adjustments, write-downs	3,000,000
Impaired loans individually evaluated for valuation adjustments, specific reserves	6,000,000
Impaired loans collectively evaluated for valuation adjustments	29,000,000
Impaired loans collectively evaluated for valuation adjustments, allowances	3,000,000
Impaired loans collectively evaluated for valuation adjustments, troubled debt restructuring	11,000,000
Impairment of real estate owned	$ 5,200,000	$ 15,100,000