Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Assets
Cash and due from banks	$ 460,217	[1]	$ 639,730	[2]	$ 552,663	[1]
Overnight investments	954,232	[1]	443,180	[2]	752,334	[1]
Investment securities available for sale	5,279,678	[1]	5,226,228	[2]	4,457,739	[1]
Investment securities held to maturity	1,229	[1]	1,342	[2]	1,688	[1]
Loans held for sale	86,351	[1]	86,333	[2]	73,457	[1]
Loans and leases:
Covered under loss share agreements	1,621,327	[1]	1,809,235	[2]	2,183,869	[1]
Not covered under loss share agreements	11,509,080	[1]	11,576,115	[2]	11,489,529	[1]
Less allowance for loan and lease losses	273,019	[1]	319,018	[2]	272,500	[1]
Net loans and leases	12,857,388	[1]	13,066,332	[2]	13,400,898	[1]
Premises and equipment	872,045	[1]	882,768	[2]	864,466	[1]
Other real estate owned:
Covered under loss share agreements	101,901	[1]	102,577	[2]	142,418	[1]
Not covered under loss share agreements	44,828	[1]	43,513	[2]	48,092	[1]
Income earned not collected	47,255	[1]	47,666	[2]	52,406	[1]
Receivable from FDIC for loss share agreements	195,942	[1]	270,192	[2]	492,384	[1]
Goodwill	102,625	[1]	102,625	[2]	102,625	[1]
Other intangible assets	2,884	[1]	3,556	[2]	6,076	[1]
Other assets	344,437	[1]	367,610	[2]	278,415	[1]
Total assets	21,351,012	[1]	21,283,652	[2]	21,225,661	[1]
Liabilities
Noninterest-bearing	4,915,038	[1]	4,885,700	[2]	4,572,300	[1]
Interest-bearing	13,149,883	[1]	13,200,325	[2]	13,187,192	[1]
Total deposits	18,064,921	[1]	18,086,025	[2]	17,759,492	[1]
Short-term borrowings	573,102	[1]	568,505	[2]	677,993	[1]
Long-term obligations	444,252	[1]	444,921	[2]	649,818	[1]
Payable to FDIC for Loss Share Agreements	98,870		101,641		82,033
Other liabilities	251,286	[1]	218,553	[2]	164,202	[1]
Total liabilities	19,432,431	[1]	19,419,645	[2]	19,333,538	[1]
Shareholders' Equity
Surplus	143,766	[1]	143,766	[2]	143,766	[1]
Retained earnings	1,845,101	[1]	1,792,726	[2]	1,804,498	[1]
Accumulated other comprehensive loss	(79,905)	[1]	(82,106)	[2]	(66,416)	[1]
Total shareholders' equity	1,918,581	[1]	1,864,007	[2]	1,892,123	[1]
Total liabilities and shareholders' equity	21,351,012	[1]	21,283,652	[2]	21,225,661	[1]
Class A Common Stock
Shareholders' Equity
Common stock	8,586	[1]	8,588	[2]	8,644	[1]
Class B Common Stock
Shareholders' Equity
Common stock	$ 1,033	[1]	$ 1,033	[2]	$ 1,631	[1]

[1] Unaudited

[2] Derived from 2012 Annual Report on Form 10-K.