Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating Activities
Net income	$ 89,021	$ 89,573
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	(9,568)	10,884
Depreciation and amortization	27,800	21,718
Net amortization of securities	5,390	5,499
Securities gains, net	(378)	(1,041)
Gains on sales of loans, net	(24,220)	(21,884)
Bargain purchase gain on acquisition	0	(3,635)
Deferred income tax provision (benefit)	14,145	(13,035)
Proceeds from sales of loans held for sale	1,156,310	1,330,506
Purchases and originations of loans held for sale	(1,021,237)	(1,419,368)
Originations and sales of mortgage servicing rights, net	(15,551)	(17,074)
Net increase in other assets	(74,411)	(46,425)
Net (decrease) increase in other liabilities	(3,431)	48,541
Other operating activities, net	7,390	17,048
Net cash provided by operating activities	151,260	1,307
Investing Activities
Proceeds from calls and maturities of securities held to maturity	7,269	12,240
Proceeds from calls and maturities of securities available for sale	642,687	692,179
Proceeds from sales of securities available for sale	67,558	34,826
Purchases of securities held to maturity	(35,045)	0
Purchases of securities available for sale	(1,000,015)	(927,652)
Net (increase) decrease in federal funds sold and securities purchased under reverse repurchase agreements	(821)	3,963
Net decrease in loans	59,025	312,194
Purchases of premises and equipment	(12,862)	(12,466)
Proceeds from sales of premises and equipment	3,782	(3)
Proceeds from sales of other real estate	30,389	26,185
Net cash received in business combination	89,037	78,151
Net cash (used in) provided by investing activities	(148,996)	219,617
Financing Activities
Net increase in deposits	150,463	28,882
Net increase (decrease) in federal funds purchased and securities sold under repurchase agreements	53,636	(195,789)
Net decrease in short-term borrowings	(21,174)	(1,613)
Payments on long-term FHLB advances	(383)	0
Redemption of junior subordinated debt securities	(33,000)	0
Common stock dividends	(46,674)	(44,941)
Common stock issued-net, long-term incentive plans	(118)	(935)
Excess tax (expense) benefit from stock-based compensation arrangements	(808)	35
Net cash provided by (used in) financing activities	101,942	(214,361)
Increase in cash and cash equivalents	104,206	6,563
Cash and cash equivalents at beginning of period	231,489	202,625
Cash and cash equivalents at end of period	$ 335,695	$ 209,188