Other Assets (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Components of other assets
Bank-Owned Life Insurance	$ 213,113,000	$ 207,843,000
Federal Home Loan Bank and Federal Reserve Bank Stock	79,946,000	79,871,000
Derivative Financial Instruments	38,085,000	30,891,000
Low-Income Housing and Other Equity Investments	35,860,000	31,995,000
Prepaid Expenses	28,979,000	38,558,000
Accounts Receivable	13,607,000	11,761,000
Federal and State Tax Deposits	6,069,000	22,341,000
Other	26,113,000	20,277,000
Total	441,772,000	443,537,000
Carrying value of Federal Home Loan Bank stock	$ 61,300,000	$ 61,300,000