Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net income	$ 133,653	$ 131,170	$ 116,061
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	16,380	15,850	15,316
Stock-based compensation	3,156	4,830	5,049
Provision for credit losses	53,335	49,456	47,992
Net amortization of premiums and accretion of discounts on securities and borrowings	11,871	12,443	9,592
Amortization of other intangible assets	9,315	7,721	6,887
Gains on securities transactions, net	(32,068)	(11,598)	(8,005)
Net impairment losses on securities recognized in earnings	19,968	4,642	6,352
Proceeds from sales of loans held for sale	366,769	385,997	369,917
Gains on sales of loans, net	(10,699)	(12,591)	(8,937)
Originations of loans held for sale	(322,281)	(323,710)	(381,930)
Gains on sales of assets, net	(426)	(619)	(605)
Change in the FDIC loss-share receivable (excluding reimbursements)	(13,403)	(6,268)
Net deferred income tax expense (benefit)	(15,285)	20,176	(10,898)
Net change in:
Trading securities	9,956	1,056	1,286
Fair value of borrowings carried at fair value	(1,256)	5,841	15,828
Cash surrender value of bank owned life insurance	(7,380)	(6,166)	(5,700)
Accrued interest receivable	(3,069)	93	1,472
Other assets	(34,977)	9,569	91,644
Accrued expenses and other liabilities	7,778	(8,878)	(166,768)
Net cash provided by operating activities	191,337	279,014	104,553
Cash flows from investing activities:
Net loan (originations) repayments	(444,207)	359,117	734,544
Loans purchased	(33,293)	(52,279)
Investment securities held to maturity:
Purchases	(683,056)	(993,407)	(967,904)
Maturities, calls and principal repayments	582,999	644,810	526,637
Investment securities available for sale:
Purchases	(473,119)	(321,318)	(503,483)
Sales	552,486	425,473	326,096
Maturities, calls and principal repayments	280,046	327,316	333,041
Death benefit proceeds from bank owned life insurance	8,469	5,241	1,727
Proceeds from sales of real estate property and equipment	4,864	4,601	3,713
Purchases of real estate property and equipment	(16,402)	(14,599)	(25,282)
Reimbursements from the FDIC	28,372
Cash and cash equivalents acquired (paid) in acquisitions		44,228	(285)
Net cash (used in) provided by investing activities	(192,841)	429,183	428,804
Cash flows from financing activities:
Net change in deposits	309,488	(837,871)	314,362
Net change in short-term borrowings	20,531	(36,517)	(424,157)
Advances of long-term borrowings		50,681
Repayments of long-term borrowings	(207,000)	(72,742)	(60,755)
Redemption of preferred stock			(300,000)
Dividends paid to preferred shareholders			(12,980)
Dividends paid to common shareholders	(116,779)	(115,190)	(109,005)
Common stock issued, net	8,027	8,391	140,008
Net cash provided by (used in) financing activities	14,267	(1,003,248)	(452,527)
Net change in cash and cash equivalents	12,763	(295,051)	80,830
Cash and cash equivalents at beginning of year	366,286	661,337	580,507
Cash and cash equivalents at end of year	379,049	366,286	661,337
Supplemental disclosures of cash flow information:
Interest on deposits and borrowings	199,565	217,102	288,858
Federal and state income taxes	60,186	50,636	63,021
Supplemental schedule of non-cash investing activities:
Transfer of investment securities held to maturity to available for sale	23,452
Loans transferred to loans held for sale		83,162
Non-cash assets acquired:
Investment securities available for sale		73,743
Loans		412,331
Premises and equipment, net		133
Accrued interest receivable		2,788
Goodwill		21,413	726
Other intangible assets, net		4,884	224
FDIC loss-share receivable		108,000
Other assets		22,558
Total non-cash assets acquired		645,850	950
Liabilities assumed:
Deposits		654,200
Short-term borrowings		12,688
Long-term borrowings		10,559
Accrued expenses and other liabilities		12,631	665
Total liabilities assumed		690,078	665
Net non-cash (liabilities) assets acquired		(44,228)	285
Cash and cash equivalents acquired (paid) in acquisitions		$ 44,228	$ (285)