Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Assets
Cash and due from banks	$ 606,107	[1]	$ 590,801	[2]	$ 539,337	[1]
Overnight investments	688,196	[1]	434,975	[2]	410,002	[1]
Investment securities available for sale	5,012,041	[1]	4,056,423	[2]	3,994,825	[1]
Investment securities held to maturity	1,459	[1]	1,822	[2]	1,943	[1]
Loans held for sale	78,610	[1]	92,539	[2]	78,178	[1]
Loans and leases:
Covered under loss share agreements	1,897,097	[1]	2,362,152	[2]	2,557,450	[1]
Not covered under loss share agreements	11,455,233	[1]	11,581,637	[2]	11,603,526	[1]
Less allowance for loan and lease losses	276,554	[1]	270,144	[2]	254,184	[1]
Net loans and leases	13,075,776	[1]	13,673,645	[2]	13,906,792	[1]
Premises and equipment	885,757	[1]	854,476	[2]	847,372	[1]
Other real estate owned:
Covered under loss share agreements	116,405	[1]	148,599	[2]	160,443	[1]
Not covered under loss share agreements	45,063	[1]	50,399	[2]	48,616	[1]
Income earned not collected	51,565	[1]	42,216	[2]	43,886	[1]
Receivable from FDIC for loss share agreements	243,893	[1]	539,511	[2]	607,907	[1]
Goodwill	102,625	[1]	102,625	[2]	102,625	[1]
Other intangible assets	4,322	[1]	7,032	[2]	8,081	[1]
Other assets	261,801	[1]	286,430	[2]	265,337	[1]
Total assets	21,173,620	[1]	20,881,493	[2]	21,015,344	[1]
Liabilities
Noninterest-bearing	4,895,588	[1]	4,331,706	[2]	4,274,945	[1]
Interest-bearing	12,997,627	[1]	13,245,568	[2]	13,388,330	[1]
Total deposits	17,893,215	[1]	17,577,274	[2]	17,663,275	[1]
Short-term borrowings	677,773	[1]	615,222	[2]	600,384	[1]
Long-term obligations	472,170	[1]	687,599	[2]	744,839	[1]
Other liabilities	156,338	[1]	140,270	[2]	135,430	[1]
Total liabilities	19,199,496	[1]	19,020,365	[2]	19,143,928	[1]
Shareholders' Equity
Surplus	143,766	[1]	143,766	[2]	143,766	[1]
Retained earnings	1,872,088	[1]	1,773,652	[2]	1,749,868	[1]
Accumulated other comprehensive loss	(51,986)	[1]	(66,574)	[2]	(32,527)	[1]
Total shareholders' equity	1,974,124	[1]	1,861,128	[2]	1,871,416	[1]
Total liabilities and shareholders' equity	21,173,620	[1]	20,881,493	[2]	21,015,344	[1]
Class A Common Stock
Shareholders' Equity
Common stock	8,629	[1]	8,644	[2]	8,669	[1]
Class B Common Stock
Shareholders' Equity
Common stock	$ 1,627	[1]	$ 1,640	[2]	$ 1,640	[1]

[1] Unaudited

[2] Derived from 2011 Annual Report on Form 10-K.