Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Assets
Cash and due from banks	$ 590,801		$ 460,178
Overnight investments	434,975		398,390
Investment securities available for sale (cost of $4,029,858 in 2011 and $4,486,881 in 2010)	4,056,423		4,510,076
Investment securities held to maturity (fair value of $1,980 in 2011 and $2,741 in 2010)	1,822		2,532
Loans held for sale	92,539		88,933
Loans and leases:
Covered under loss share agreements	2,362,152	[1]	2,007,452	[1]
Not covered under loss share agreements	11,581,637		11,480,577
Less allowance for loan and lease losses	270,144		227,765
Net loans and leases	13,673,645		13,260,264
Premises and equipment	854,476		842,745
Other real estate owned:
Covered under loss share agreements	148,599		112,748
Not covered under loss share agreements	50,399		52,842
Income earned not collected	42,216		83,644
Receivable from FDIC for loss share agreements	539,511		623,261
Goodwill	102,625		102,625
Other intangible assets	7,032		9,897
Other assets	286,430		258,524
Total assets	20,881,493		20,806,659
Deposits:
Noninterest-bearing	4,331,706		3,976,366
Interest-bearing	13,245,568		13,658,900
Total deposits	17,577,274		17,635,266
Short-term borrowings	615,222		546,597
Long-term obligations	687,599		809,949
Other liabilities	140,270		81,885
Total liabilities	19,020,365		19,073,697
Shareholders' Equity
Surplus	143,766		143,766
Retained earnings	1,773,652		1,615,290
Accumulated other comprehensive loss	(66,574)		(36,529)
Total shareholders' equity	1,861,128		1,732,962
Total liabilities and shareholders' equity	20,881,493		20,806,659
Class A Common Stock [Member]
Shareholders' Equity
Common stock	8,644		8,757
Class B Common Stock [Member]
Shareholders' Equity
Common stock	$ 1,640		$ 1,678

[1] Covered loans are acquired loans subject to loss share agreements with the FDIC.