Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Activities
Net income	$ 43,050	$ 23,090	$ 10,003
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	26,000	45,600	59,000
Gains on sales of loans	(5,017)	(5,986)	(6,431)
Proceeds from sales of loans	224,341	281,511	367,796
Loans originated for sale	(217,663)	(286,317)	(361,264)
Proceeds from sale of trading securities		1,083
Investment securities net gains			(95)
Net gains on sales of other real estate and repossessed assets	(2,208)	(1,394)	(969)
Net (gain) loss on disposal of premises and equipment, branch bank properties and insurance settlement	616	865	(162)
Depreciation of premises and equipment	7,950	7,826	6,429
Amortization of intangible assets	3,615	3,609	2,569
Net amortization of premiums and discounts on investment securities	4,024	2,818	815
Share-based compensation expense	1,517	1,395	490
Deferred income tax	6,413	3,439	(6,977)
Contributions to defined benefit pension plan		(10,000)	(7,500)
Net (increase) decrease in interest receivable and other assets	10,747	350	(17,973)
Net increase (decrease) in interest payable and other liabilities	(909)	9,325	306
Net Cash Provided by Operating Activities	102,476	77,214	46,037
Investment securities - available-for-sale:
Proceeds from maturities, calls and principal reductions	327,013	333,878	264,998
Proceeds from sales			78
Purchases	(419,714)	(253,815)	(408,344)
Investment securities - held-to-maturity:
Proceeds from maturities, calls and principal reductions	52,115	47,150	41,511
Purchases	(70,014)	(81,346)	(75,219)
Net increase in loans	(196,484)	(124,985)	(64,754)
Proceeds from sales of other real estate and repossessed assets	19,202	18,066	16,950
Proceeds from sales of branch bank properties and insurance settlement		58	433
Purchases of premises and equipment, net	(8,602)	(7,791)	(7,431)
Purchase of bank owned life insurance	(3,600)
Cash acquired, net of cash paid, in business combination		17,177
Net Cash Used in Investing Activities	(300,084)	(51,608)	(231,778)
Financing Activities
Net increase in noninterest-bearing and interest-bearing demand deposits and savings accounts	113,164	200,829	222,222
Net increase (decrease) in time deposits	(78,072)	19,570	217,111
Net increase in short-term borrowings	61,083	2,135	6,830
Repayment of FHLB advances	(31,073)	(51,733)	(45,025)
Cash dividends paid	(21,964)	(21,243)	(28,190)
Proceeds from directors' stock purchase plan and exercise of stock options	245	292	280
Net Cash Provided by Financing Activities	43,383	149,850	373,228
Net Increase (Decrease) in Cash and Cash Equivalents	(154,225)	175,456	187,487
Cash and Cash Equivalents at Beginning of Year	536,165	360,709	173,222
Cash and Cash Equivalents at End of Year	381,940	536,165	360,709
Supplemental Disclosures of Cash Flow Information
Interest paid	32,129	40,206	46,232
Federal income taxes paid	7,787	9,800	9,725
Loans transferred to other real estate and repossessed assets	19,664	26,429	18,320
Business combination:
Fair value of tangible assets acquired (noncash)		749,916
Goodwill and identifiable intangible assets acquired		53,310
Liabilities assumed		736,706
Common stock and stock options issued		$ 83,697