CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 143,627	$ 132,511	$ 130,006
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	18,477	16,380	15,850
Stock-based compensation	4,816	3,156	4,830
Provision for credit losses	25,552	53,335	49,456
Net amortization of premiums and accretion of discounts on securities and borrowings	21,124	11,871	12,443
Amortization of other intangible assets	9,783	9,315	7,721
Gains on securities transactions, net	(2,587)	(32,068)	(11,598)
Net impairment losses on securities recognized in earnings	5,247	19,968	4,642
Proceeds from sales of loans held for sale	999,380	366,769	385,997
Gains on sales of loans, net	(46,998)	(10,699)	(12,591)
Originations of loans held for sale	(923,182)	(322,281)	(323,710)
Losses (gains) on sales of assets, net	329	(426)	(619)
Net deferred income tax expense (benefit)	28,398	(16,111)	19,334
Net change in:
FDIC loss-share receivable (excluding reimbursements)	7,459	(13,403)	(6,268)
Trading securities	(219)	9,956	1,056
Fair value of borrowings carried at fair value	(2,574)	(1,256)	5,841
Cash surrender value of bank owned life insurance	(6,855)	(7,380)	(6,166)
Accrued interest receivable	5,446	(3,069)	93
Other assets	49,345	(34,977)	9,569
Accrued expenses and other liabilities	(13,257)	9,746	(6,872)
Net cash provided by operating activities	323,311	191,337	279,014
Cash flows from investing activities:
Net loan (originations) repayments	(203,354)	(444,207)	359,117
Loans purchased	(136,241)	(33,293)	(52,279)
Investment securities held to maturity:
Purchases	(360,614)	(683,056)	(993,407)
Maturities, calls and principal repayments	705,487	582,999	644,810
Investment securities available for sale:
Purchases	(455,601)	(473,119)	(321,318)
Sales	257,497	552,486	425,473
Maturities, calls and principal repayments	248,721	280,046	327,316
Death benefit proceeds from bank owned life insurance	1,689	8,469	5,241
Proceeds from sales of real estate property and equipment	9,337	4,864	4,601
Purchases of real estate property and equipment	(22,735)	(16,402)	(14,599)
Reimbursements from the FDIC under loss-sharing agreements	21,935	28,372
Cash and cash equivalents acquired in acquisitions	117,587		44,228
Net cash provided by (used in) investing activities	183,708	(192,841)	429,183
Cash flows from financing activities:
Net change in deposits	210,623	309,488	(837,871)
Net change in short-term borrowings	(87,526)	20,531	(36,517)
Advances of long-term borrowings			50,681
Repayments of long-term borrowings	(28,000)	(207,000)	(72,742)
Redemption of junior subordinated debentures	(10,000)
Cash dividends paid to common shareholders	(125,870)	(116,779)	(115,190)
Common stock issued, net	7,805	8,027	8,391
Net cash (used in) provided by financing activities	(32,968)	14,267	(1,003,248)
Net change in cash and cash equivalents	474,051	12,763	(295,051)
Cash and cash equivalents at beginning of year	379,049	366,286	661,337
Cash and cash equivalents at end of year	853,100	379,049	366,286
Supplemental disclosures of cash flow information:
Interest on deposits and borrowings	183,120	199,565	217,102
Federal and state income taxes	50,111	60,186	50,636
Supplemental schedule of non-cash investing activities:
Transfer of investment securities held to maturity to available for sale		23,452
Transfer of loans to other real estate owned	14,365	10,707	9,544
Transfer of loans to loans held for sale	124,261		83,162
Non-cash assets acquired:
Investment securities available for sale	275,650		73,743
Loans	1,088,421		412,331
Premises and equipment, net	9,457		133
Accrued interest receivable	5,294		2,788
Goodwill	109,758		21,413
Other intangible assets, net	8,050		4,884
FDIC loss-share receivable			108,000
Other assets	72,137		22,558
Total non-cash assets acquired	1,568,767		645,850
Liabilities assumed:
Deposits	1,380,293		654,200
Short-term borrowings	29,000		12,688
Long-term borrowings			10,559
Junior subordinated debentures issued to capital trusts	15,645
Accrued expenses and other liabilities	52,998		12,631
Total liabilities assumed	1,477,936		690,078
Net non-cash assets (liabilities) acquired	90,831		(44,228)
Net cash and cash equivalents acquired in acquisitions	117,587		44,228
Common stock issued in acquisitions	$ 208,418	$ 208,418