Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Operating Activities
Net income	$ 89,573	$ 82,583
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	10,884	23,631
Depreciation and amortization	21,718	18,523
Net amortization of securities	5,499	6,092
Securities gains, net	(1,041)	(91)
Gains on sales of loans, net	(21,884)	(7,320)
Decrease in FDIC indemnification asset	360	117
Bargain purchase gain on acquisition	(3,635)	(7,456)
Deferred income tax benefit	(13,035)	(6,735)
Proceeds from sales of loans held for sale	1,330,506	664,099
Purchases and originations of loans held for sale	(1,419,368)	(692,958)
Originations and sales of mortgage servicing rights, net	(17,075)	(9,581)
Net (increase) decrease in other assets	(46,784)	40,930
Net increase (decrease) in other liabilities	48,541	(3,898)
Other operating activities, net	17,048	25,278
Net cash provided by operating activities	1,307	133,214
Investing Activities
Proceeds from calls and maturities of securities held to maturity	12,240	69,874
Proceeds from calls and maturities of securities available for sale	692,179	482,918
Proceeds from sales of securities available for sale	34,826	22,996
Purchases of securities available for sale	(927,652)	(747,383)
Net decrease in federal funds sold and securities purchased under reverse repurchase agreements	3,963	3,963
Net decrease in loans	312,194	227,687
Purchases of premises and equipment	(12,466)	(8,393)
Proceeds from sales of premises and equipment	(3)	536
Proceeds from sales of other real estate	26,185	36,277
Net cash received in business combination	78,151	78,896
Net cash provided by investing activities	219,617	167,371
Financing Activities
Net increase in deposits	28,882	320,808
Net decrease in federal funds purchased and securities sold under repurchase agreements	(195,789)	(123,466)
Net decrease in short-term borrowings	(1,613)	(369,765)
Payments from calls of long-term FHLB advances	0	(153)
Common stock dividends	(44,941)	(44,614)
Common stock issued-net, long-term incentive plans	(935)	(360)
Excess tax benefit from stock-based compensation arrangements	35	553
Net cash used in financing activities	(214,361)	(216,997)
Increase in cash and cash equivalents	6,563	83,588
Cash and cash equivalents at beginning of period	202,625	161,544
Cash and cash equivalents at end of period	$ 209,188	$ 245,132