Fair Value Measurements Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
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	$ 2,687,957,000
Significant Input, Assumed Market Return to Liquidity, Years	5 years
Other real estate owned (OREO)	23,820,000	26,146,000
Short Term Borrowings, Reprice Period, In Days	90
Minimum [Member]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed	9.50%
Maximum [Member]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed	15.40%
Equity Securities [Member]
Restricted equity securities issued by the Federal Home Loan Bank and Federal Reserve Bank	74,500,000	71,700,000
Equity Securities Financial Institution [Member]
Available-for-sale Securities, Equity Securities	42,500,000	44,200,000
Equity Securities, Other [Member]
Available-for-sale Securities, Equity Securities	6,900,000	6,700,000
Corporate Debt Securities [Member]
Corporate debt securities	115,044,000	112,842,000
Single-issuer Trust Preferred Securities [Member]
Corporate debt securities	52,523,000	51,656,000
Pooled Trust Preferred Securities [Member]
Corporate debt securities	8,356,000	6,927,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities Financial Institution [Member]
Available-for-sale Securities, Equity Securities	42,500,000	44,200,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities, Other [Member]
Available-for-sale Securities, Equity Securities	6,900,000	6,700,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Financial Institutions Subordinated Debt [Member]
Corporate debt securities	51,700,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Single-issuer Trust Preferred Securities [Member]
Corporate debt securities	49,100,000	48,300,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Corporate Debt [Member]
Corporate debt securities	2,500,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Single-issuer Trust Preferred Securities [Member]
Corporate debt securities	52,500,000	51,700,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Corporate debt securities		6,900,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Single-issuer Trust Preferred Securities [Member]
Corporate debt securities	3,400,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Pooled Trust Preferred Securities [Member]
Corporate debt securities	8,400,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Other real estate owned (OREO)	23,800,000	26,100,000
Servicing Asset at Amortized Value, Fair Value	37,300,000	36,100,000
Trust for Benefit of Employees [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Other financial assets	14,000,000	14,100,000
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Other financial assets	1,800,000	1,200,000
Forward Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Other financial assets	4,800,000	7,600,000
Other financial liabilities	369,000	1,100,000
Interest Rate Swap [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Other financial assets	6,700,000	7,100,000
Other financial liabilities	6,700,000	7,100,000
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Other financial liabilities	1,200,000	1,500,000
Trust for Benefit of Employees [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Other financial liabilities	$ 14,000,000	$ 14,100,000