Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Activities
Net income	$ 24,866	$ 30,320
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	(2,838)	3,099
Depreciation and amortization	8,380	6,589
Net amortization of securities	1,868	1,618
Securities gains, net	(204)	(1,050)
Gains on sales of loans, net	(10,165)	(6,460)
Bargain purchase gain on acquisition	0	(2,754)
Deferred income tax provision	2,157	1,880
Proceeds from sales of loans held for sale	402,159	378,255
Purchases and originations of loans held for sale	(382,425)	(388,370)
Originations and sales of mortgage servicing rights, net	(5,521)	(4,478)
Net (increase) decrease in other assets	(45,074)	4,000
Net (decrease) increase in other liabilities	(5,740)	10,674
Other operating activities, net	1,903	2,993
Net cash (used in) provided by operating activities	(10,634)	36,316
Investing Activities
Proceeds from calls and maturities of securities held to maturity	3,580	5,699
Proceeds from calls and maturities of securities available for sale	272,858	234,155
Proceeds from sales of securities available for sale	38,742	0
Purchases of securities held to maturity	(35,045)	0
Purchases of securities available for sale	(667,299)	(374,785)
Net decrease in federal funds sold and securities purchased under reverse repurchase agreements	1,120	2,957
Net decrease in loans	145,517	74,593
Purchases of premises and equipment	(2,228)	(6,909)
Proceeds from sales of other real estate	8,297	10,039
Net cash received in business combinations	89,037	78,151
Net cash (used in) provided by investing activities	(145,421)	23,900
Financing Activities
Net increase in deposits	272,660	315,587
Net decrease in federal funds purchased and securities sold under repurchase agreements	(69,060)	(349,622)
Net (decrease) increase in short-term borrowings	(19,936)	74
Payments on long-term FHLB advances	(82)	0
Common stock dividends	(15,560)	(14,900)
Common stock issued-net, long-term incentive plans	(829)	(1,154)
Excess tax benefit from stock-based compensation arrangements	269	674
Net cash provided by (used in) financing activities	167,462	(49,341)
Increase in cash and cash equivalents	11,407	10,875
Cash and cash equivalents at beginning of period	231,489	202,625
Cash and cash equivalents at end of period	$ 242,896	$ 213,500