Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
OPERATING ACTIVITIES
Net income	$ 195,028	$ 193,044	$ 116,331
Adjustments to reconcile net income to cash provided by operating activities:
Provision for loan and lease losses	232,277	143,519	79,364
Deferred tax (benefit) expense	(16,786)	(41,375)	35,772
Change in current taxes payable	(2,820)	(25,432)	(4,426)
Depreciation	65,170	62,761	57,724
Change in accrued interest payable	(14,340)	(877)	(13,042)
Change in income earned not collected	48,423	(15,300)	17,083
Gain on acquisitions	(150,417)	(136,000)	(104,434)
Securities losses (gains)	288	(1,952)	511
Origination of loans held for sale	(513,253)	(605,302)	(751,154)
Proceeds from sale of loans held for sale	518,398	592,608	761,973
Gain on sale of loans held for sale	(8,751)	(8,858)	(8,801)
(Gain) loss on sale of other real estate	53,450	15,633	18,010
Gain on repayment of long-term obligations	(9,685)	0	0
Net amortization of premiums and accretions of discounts	(237,218)	(139,607)	45,186
Change in FDIC receivable for loss share agreements	380,402	99,228	(2,800)
Net change in other assets	89,979	(6,810)	(50,636)
Net change in other liabilities	(1,392)	21,455	(28,585)
Net cash provided by operating activities	628,753	146,735	168,076
INVESTING ACTIVITIES
Net change in loans and leases outstanding	473,974	926,122	49,677
Purchases of investment securities held to maturity	0	0	(73)
Purchases of investment securities available for sale	(3,480,699)	(4,192,967)	(1,462,593)
Proceeds from maturities of investment securities held to maturity	709	1,069	2,343
Proceeds from maturities of investment securities available for sale	4,002,724	2,592,097	1,567,326
Proceeds from sales of investment securities available for sale	242,023	38,496	151,559
Net change in overnight investments	(36,585)	324,870	(417,372)
Proceeds from sale of other real estate	135,803	143,740	10,763
Additions to premises and equipment	(76,901)	(70,836)	(95,877)
Dispositions of premises and equipment	0	1,316	0
Net cash received from acquisitions	1,150,879	106,489	51,381
Net cash provided (used) by investing activities	2,411,927	(129,604)	(142,866)
FINANCING ACTIVITIES
Net change in time deposits	(2,273,418)	(743,191)	(1,102,587)
Net change in demand and other interest-bearing deposits	4,417	1,333,159	1,051,869
Net change in short-term borrowings	(283,440)	(500,217)	(83,719)
Retirement of long-term obligations	(320,730)	(114,425)
Origination of long-term obligations	0	0	8,616
Repurchase of common stock	(24,387)	0	0
Cash dividends paid	(12,499)	(12,521)	(12,522)
Net cash provided (used) by financing activities	(2,910,057)	(37,195)	(138,343)
Change in cash and due from banks	130,623	(20,064)	(113,133)
Cash and due from banks at beginning of period	460,178	480,242	593,375
Cash and due from banks at end of period	590,801	460,178	480,242
CASH PAYMENTS FOR:
Interest	157,477	196,002	240,686
Income taxes	91,465	187,183	20,640
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Unrealized securities gains (losses)	3,370	(12,574)	(38,913)
Unrealized (loss) gain on cash flow hedge	(1,222)	(4,125)	5,301
Prepaid pension benefit (pension liability)	(51,559)	(2,804)	53,703
Transfers of loans to other real estate	213,195	156,918	67,380
Acquisitions:
Assets acquired	2,934,464	2,291,659	1,924,179
Liabilities assumed	2,784,047	2,155,861	1,819,745
Net assets acquired	$ 150,417	$ 135,798	$ 104,434