Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating Activities
Net income	$ 61,900	$ 55,987
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	3,393	(9,236)
Depreciation and amortization	17,956	18,317
Net amortization of securities	3,964	3,779
Securities gains, net	(389)	(378)
Gains on sales of loans, net	(4,584)	(17,759)
Deferred income tax provision	14,000	16,971
Proceeds from sales of loans held for sale	402,463	801,767
Purchases and originations of loans held for sale	(394,266)	(761,540)
Originations and sales of mortgage servicing rights, net	(5,179)	(10,661)
Increase in bank-owned life insurance	(2,337)	(334)
Net (increase) decrease in other assets	(99)	9,034
Net decrease in other liabilities	(15,827)	(3,064)
Other operating activities, net	10,151	2,600
Net cash provided by operating activities	91,146	105,483
Investing Activities
Proceeds from calls and maturities of securities held to maturity	39,903	6,905
Proceeds from calls and maturities of securities available for sale	166,089	482,993
Proceeds from sales of securities available for sale	26,274	67,558
Purchases of securities held to maturity	(25,252)	(35,045)
Purchases of securities available for sale	(360,703)	(950,009)
Net decrease (increase) in federal funds sold and securities purchased under reverse repurchase agreements	2,253	(823)
Net (increase) decrease in loans	(256,722)	113,671
Purchases of premises and equipment	(6,132)	(7,562)
Proceeds from sales of premises and equipment	4,632	10
Proceeds from sales of other real estate	21,672	17,060
Net cash received in business combinations	0	89,037
Net cash used in investing activities	(387,986)	(216,205)
Financing Activities
Net increase in deposits	464	180,821
Net increase in federal funds purchased and securities sold under repurchase agreements	307,729	85,192
Net decrease in short-term borrowings	(1,673)	(19,596)
Payments on long-term FHLB advances	(109)	(229)
Redemption of junior subordinated debt securities	0	(33,000)
Common stock dividends	(31,224)	(31,108)
Common stock issued-net, long-term incentive plans	(795)	(568)
Excess tax expense from stock-based compensation arrangements	(353)	(747)
Net cash provided by financing activities	274,039	180,765
(Decrease) Increase in cash and cash equivalents	(22,801)	70,043
Cash and cash equivalents at beginning of period	345,761	231,489
Cash and cash equivalents at end of period	$ 322,960	$ 301,532