Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating Activities
Net income	$ 55,987	$ 59,669
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses, net	(9,236)	5,421
Depreciation and amortization	18,317	13,856
Net amortization of securities	3,779	3,464
Securities gains, net	(378)	(1,042)
Gains on sales of loans, net	(17,759)	(12,771)
Bargain purchase gain on acquisition	0	(3,635)
Deferred income tax provision	16,971	1,855
Proceeds from sales of loans held for sale	801,767	807,588
Purchases and originations of loans held for sale	(761,540)	(873,700)
Originations and sales of mortgage servicing rights, net	(10,661)	(10,411)
Net decrease (increase) in other assets	8,700	(6,547)
Net (decrease) increase in other liabilities	(3,064)	9,433
Other operating activities, net	2,600	12,325
Net cash provided by operating activities	105,483	5,505
Investing Activities
Proceeds from calls and maturities of securities held to maturity	6,905	9,850
Proceeds from calls and maturities of securities available for sale	482,993	453,647
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	(950,009)	(591,493)
Net (increase) decrease in federal funds sold and securities purchased under reverse repurchase agreements	(823)	2,533
Net decrease in loans	113,671	196,961
Purchases of premises and equipment	(7,562)	(9,849)
Proceeds from sales of premises and equipment	10	0
Proceeds from sales of other real estate	17,060	18,816
Net cash received in business combination	89,037	78,151
Net cash (used in) provided by investing activities	(216,205)	193,442
Financing Activities
Net increase in deposits	180,821	220,698
Net increase (decrease) in federal funds purchased and securities sold under repurchase agreements	85,192	(306,831)
Net (decrease) increase in short-term borrowings	(19,596)	181
Payments on long-term FHLB advances	(229)	0
Redemption of junior subordinated debt securities	(33,000)	0
Common stock dividends	(31,108)	(29,921)
Common stock issued-net, long-term incentive plans	(568)	(1,013)
Excess tax (expense) benefit from stock-based compensation arrangements	(747)	49
Net cash provided by (used in) financing activities	180,765	(116,837)
Increase in cash and cash equivalents	70,043	82,110
Cash and cash equivalents at beginning of period	231,489	202,625
Cash and cash equivalents at end of period	$ 301,532	$ 284,735