Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash Flows From Operating Activities:
Net Income	$ 31,846	$ 15,551
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	20,900	35,300
Gains on sales of loans	(3,373)	(3,867)
Proceeds from sales of loans	150,299	187,646
Loans originated for sale	(141,659)	(193,639)
Proceeds from sale of trading securities		1,083
Investment securities gains		(82)
Net gains on sales of other real estate and repossessed assets	(974)	(1,214)
Net losses on disposal of premises and equipment and branch bank property	225	865
Depreciation of premises and equipment	6,026	5,795
Amortization of intangible assets	2,700	2,376
Net amortization of premiums and discounts on investment securities	2,809	2,022
Share-based compensation expense	702	1,343
Net decrease in interest receivable and other assets	6,002	1,029
Net decrease in interest payable and other liabilities	(3,371)	(3,341)
Net cash provided by operating activities	72,132	50,867
Investment securities--available-for-sale:
Proceeds from maturities, calls and principal reductions	269,373	247,265
Purchases	(303,760)	(196,203)
Investment securities--held-to-maturity:
Proceeds from maturities, calls and principal reductions	43,854	35,014
Purchases	(64,793)	(59,255)
Other securities:
Proceeds from redemption	1,561	1,259
Net increase in loans	(114,810)	(59,078)
Proceeds from sales of other real estate and repossessed assets	12,801	13,242
Purchases of premises and equipment and branch bank property, net	(5,288)	(5,978)
Cash acquired, net of cash paid, in business combination		17,177
Net cash used in investing activities	(161,062)	(6,557)
Cash Flows From Financing Activities:
Net increase in noninterest-bearing and interest-bearing demand deposits and savings accounts	204,092	382,936
Net decrease in time deposits	(55,271)	(26,900)
Net increase in securities sold under agreements to repurchase	59,595	14,231
Repayment of FHLB advances	(28,139)	(40,473)
Cash dividends paid	(16,473)	(15,755)
Proceeds from directors' stock plans and exercise of stock options	245	292
Net cash provided by financing activities	164,049	314,331
Net increase in cash and cash equivalents	75,119	358,641
Cash and cash equivalents at beginning of period	536,165	360,709
Cash and Cash Equivalents at End of Period	611,284	719,350
Supplemental Disclosure of Cash Flow Information:
Interest paid	24,804	30,634
Federal income taxes paid	2,952	8,650
Loans transferred to other real estate and repossessed assets	14,329	15,252
Business combination:
Fair value of tangible assets acquired (noncash)		752,554
Goodwill and identifiable intangible assets acquired		50,672
Liabilities assumed		736,706
Shares and stock options issued in the acquisition of O.A.K. Financial Corporation		$ 83,697