Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest Income
Interest and fees on loans	$ 209,429	$ 195,590	$ 193,193
Interest on investment securities:
Taxable	9,147	10,234	9,890
Tax-exempt	7,054	6,394	5,931
Dividends on nonmarketable equity securities	1,224	1,105	1,041
Interest on deposits with the Federal Reserve Bank and other banks	407	738	703
Total Interest Income	227,261	214,061	210,758
Interest Expense
Interest on deposits	14,254	16,883	21,782
Interest on short-term borrowings	414	484	426
Interest on long-term FHLB advances and subordinated debt	42	47	1,005
Total Interest Expense	14,710	17,414	23,213
Net Interest Income	212,551	196,647	187,545
Provision for loan losses	6,100	11,000	18,500
Net Interest Income after Provision for Loan Losses	206,451	185,647	169,045
Noninterest Income
Service charges and fees on deposit accounts	22,414	21,939	19,581
Wealth management revenue	16,015	13,989	11,763
Other charges and fees for customer services	18,578	17,151	14,227
Mortgage banking revenue	5,041	5,336	6,597
Gain on sale of investment securities	0	1,133	34
Gain on sale of merchant card services	400	0	1,280
Other	647	861	1,202
Total Noninterest Income	63,095	60,409	54,684
Operating Expenses
Salaries, wages and employee benefits	104,218	96,419	84,383
Occupancy	15,842	13,934	12,413
Equipment and software	15,297	13,734	13,112
Other	44,568	40,861	42,013
Total Operating Expenses	179,925	164,948	151,921
Income Before Income Taxes	89,621	81,108	71,808
Federal income tax expense	27,500	24,300	20,800
Net Income	$ 62,121	$ 56,808	$ 51,008
Net Income Per Common Share
Basic	$ 1.98	$ 2.02	$ 1.86
Diluted	$ 1.97	$ 2.00	$ 1.85
Cash Dividends Declared Per Common Share	$ 0.94	$ 0.87	$ 0.82