Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Allowances for losses	$ 55,057	$ 60,138
Compensation and benefits (principally pension and other postretirement benefit plans)	53,167	72,240
Securities impairment write-downs		42,322
Mortgage loans (principally deferred loan origination costs)	9,029	6,810
Effect of unrecognized tax benefits, related accrued interest and other deductible temporary differences	7,238	6,941
Total gross deferred tax assets	124,491	188,451
Deferred tax liabilities:
Premises and equipment	(3,124)	(3,162)
Net unrealized gain on securities available-for-sale	(2,432)	(6,139)
Total gross deferred tax liabilities	(5,556)	(9,301)
Net deferred tax assets (included in other assets)	$ 118,935	$ 179,150