Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest, fee, and dividend income
Interest and fees on loans	$ 208,458	$ 204,370	$ 213,429
Securities available for sale	27,005	31,083	36,167
Securities held to maturity	2,378	2,886	3,968
Other	1,556	1,658	2,174
Total interest, fee, and dividend income	239,397	239,997	255,738
Interest expense
Deposits	18,848	23,020	30,354
Short-term borrowings	188	205	402
Long-term debt	14,428	14,404	18,314
Trust preferred debentures	1,730	2,092	4,140
Total interest expense	35,194	39,721	53,210
Net interest income	204,203	200,276	202,528
Provision for loan losses	20,269	20,737	29,809
Net interest income after provision for loan losses	183,934	179,539	172,719
Noninterest income
Insurance and other financial services revenue	22,387	20,843	18,867
Service charges on deposit accounts	18,225	21,464	24,041
ATM and debit card fees	12,358	11,642	10,035
Retirement plan administration fees	10,097	8,918	10,356
Trust	9,172	8,864	7,722
Bank owned life insurance income	3,077	3,085	3,316
Net securities gains	599	150	3,274
Other	11,412	5,345	6,277
Total noninterest income	87,327	80,311	83,888
Noninterest expense
Salaries and employee benefits	104,815	99,212	93,718
Occupancy	17,415	16,363	15,350
Data processing and communications	13,437	12,271	12,347
Professional fees and outside services	10,463	8,921	9,032
Equipment	9,627	8,864	8,317
Office supplies and postage	6,489	6,073	6,102
FDIC expenses	3,832	4,267	6,081
Advertising	2,889	3,460	3,487
Amortization of intangible assets	3,394	3,046	3,072
Loan collection and other real estate owned	2,560	2,631	3,036
Merger expenses	2,608	804	0
Prepayment penalty on long-term debt	0	0	4,526
Other	16,358	14,764	13,223
Total noninterest expense	193,887	180,676	178,291
Income before income tax expense	77,374	79,174	78,316
Income tax expense	22,816	21,273	20,912
Net income	$ 54,558	$ 57,901	$ 57,404
Earnings per share
Basic (in dollars per share)	$ 1.63	$ 1.72	$ 1.67
Diluted (in dollars per share)	$ 1.62	$ 1.71	$ 1.66