Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
OPERATING ACTIVITIES
Net income	$ 134,348	$ 195,028	$ 193,044
Adjustments to reconcile net income to cash provided by operating activities:
Provision for loan and lease losses	142,885	232,277	143,519
Deferred tax benefit	(35,265)	(16,637)	(41,375)
Change in current taxes payable	29,095	(2,820)	(25,432)
Depreciation	68,941	65,170	62,761
Change in accrued interest payable	(14,366)	(14,340)	(877)
Change in income earned not collected	(5,450)	48,423	(15,300)
Gain on acquisitions	0	(150,417)	(136,000)
Securities losses (gains)	(2,277)	288	(1,952)
Origination of loans held for sale	(575,705)	(513,253)	(605,302)
Proceeds from sale of loans held for sale	589,376	518,398	592,608
Gain on sale of loans held for sale	(7,465)	(8,751)	(8,858)
Loss on other real estate	36,229	53,450	15,633
Gain on retirement of long-term obligations	0	(9,685)	0
Net amortization of premiums and accretions of discounts	(158,227)	(194,434)	(119,085)
Change in FDIC receivable for loss share agreements	(7,181)	44,551	26,284
Net change in other assets	(17,617)	89,979	(6,810)
Net change in other liabilities	23,967	(1,541)	21,455
Net cash provided by operating activities	201,288	335,686	94,313
INVESTING ACTIVITIES
Net change in loans and leases outstanding	627,806	473,974	926,122
Purchases of investment securities available for sale	(5,169,641)	(3,480,699)	(4,192,967)
Proceeds from maturities of investment securities held to maturity	480	709	1,069
Proceeds from maturities of investment securities available for sale	3,986,370	4,002,724	2,592,097
Proceeds from sales of investment securities available for sale	7,900	242,023	38,496
Net change in overnight investments	(8,205)	(36,585)	324,870
Cash received from the FDIC for loss share agreements	251,972	293,067	52,422
Proceeds from sale of other real estate	147,858	135,803	143,740
Additions to premises and equipment	(88,883)	(76,901)	(70,836)
Dispositions of premises and equipment	0	0	1,316
Net cash received from acquisitions	0	1,150,879	106,489
Net cash provided (used) by investing activities	(244,343)	2,704,994	(77,182)
FINANCING ACTIVITIES
Net change in time deposits	(1,049,761)	(2,273,418)	(743,191)
Net change in demand and other interest-bearing deposits	1,558,512	4,417	1,333,159
Net change in short-term borrowings	(101,717)	(283,440)	(500,217)
Retirement of long-term obligations	(196,338)	(320,730)	(114,425)
Origination of long-term obligations	310	0	0
Repurchase of common stock	(103,624)	(24,387)	0
Cash dividends paid	(15,398)	(12,499)	(12,521)
Net cash provided (used) by financing activities	91,984	(2,910,057)	(37,195)
Change in cash and due from banks	48,929	130,623	(20,064)
Cash and due from banks at beginning of period	590,801	460,178	480,242
Cash and due from banks at end of period	639,730	590,801	460,178
CASH PAYMENTS FOR:
Interest	104,514	157,477	196,002
Income taxes	66,453	91,465	187,183
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized securities gains (losses)	7,244	3,370	(12,574)
Change in fair value of cash flow hedges	316	(1,222)	(4,125)
Change in pension obligation	(33,079)	(51,559)	(2,804)
Transfers of loans to other real estate	140,645	213,195	156,918
Acquisitions:
Assets acquired	0	2,934,464	2,291,659
Liabilities assumed	0	2,784,047	2,155,861
Net assets acquired	$ 0	$ 150,417	$ 135,798