Fair Value Measurements Narrative (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Equity Securities, Value Test Coverage, Percent	80.00%
Fair Value, Equity Securities, Fair Value Price Difference Threshold, Percent	5.00%
Corporate debt securities	$ 2,556,248,000
Other real estate owned (OREO)	30,803,000	32,959,000
Equity Securities [Member]
Restricted equity securities issued by the Federal Home Loan Bank and Federal Reserve Bank	82,500,000	96,400,000
Fair Value, Inputs, Level 3 [Member] | Other Assets [Member]
Other real estate owned (OREO)	30,800,000	33,000,000
Servicing Asset at Amortized Value, Fair Value	33,100,000	29,100,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Restricted equity securities issued by the Federal Home Loan Bank and Federal Reserve Bank	82,500,000	96,400,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities Financial Institution [Member]
Available-for-sale Securities, Equity Securities	27,900,000	33,100,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities, Other [Member]
Available-for-sale Securities, Equity Securities	6,700,000	7,000,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Financial Institutions Subordinated Debt [Member]
Corporate debt securities	41,300,000	35,900,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Single-issuer Trust Preferred Securities [Member]
Corporate debt securities	70,200,000	73,200,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Corporate Debt [Member]
Corporate debt securities	2,500,000	2,600,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Single-issuer Trust Preferred Securities [Member]
Investments, Fair Value Disclosure		800,000
Corporate debt securities	4,200,000	8,600,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Pooled Trust Preferred Securities [Member]
Corporate debt securities	5,100,000	4,500,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Single-issuer Trust Preferred Securities [Member]
Corporate debt securities	$ 74,400,000	$ 81,800,000