CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Interest income:
Loans and leases	$ 161,137	$ 161,376	$ 163,986
Investment securities, taxable	14,414	16,426	18,533
Investment securities, tax-exempt	3,094	3,340	4,013
Other	940	943	991
Total interest income	179,585	182,085	187,523
Interest expense:
Deposits	16,604	21,877	30,762
Short-term borrowings	211	169	300
Subordinated notes	4,220	6,484	6,589
Long-term debt and mandatorily redeemable securities	1,733	1,779	1,472
Total interest expense	22,768	30,309	39,123
Net interest income	156,817	151,776	148,400
Provision for loan and lease losses	772	5,752	3,129
Net interest income after provision for loan and lease losses	156,045	146,024	145,271
Noninterest income:
Trust fees	17,383	16,498	16,327
Service charges on deposit accounts	9,177	10,418	10,993
Debit card income	8,882	8,389	7,495
Mortgage banking income	5,944	8,357	3,839
Insurance commissions	5,492	5,494	4,793
Equipment rental income	16,229	18,796	23,361
Investment securities and other investment gains	454	580	1,399
Other income	13,651	12,660	12,665
Total noninterest income	77,212	81,192	80,872
Noninterest expense:
Salaries and employee benefits	79,783	82,599	77,261
Net occupancy expense	8,700	7,819	8,714
Furniture and equipment expense	16,895	15,406	14,130
Depreciation — leased equipment	13,055	15,202	18,650
Professional fees	5,321	6,083	5,508
Supplies and communications	5,690	5,701	5,453
FDIC and other insurance	3,462	3,602	4,421
Business development and marketing expense	4,938	4,232	4,032
Loan and lease collection and repossession expense	4,030	5,772	6,724
Other expense	7,440	5,120	7,461
Total noninterest expense	149,314	151,536	152,354
Income before income taxes	83,943	75,680	73,789
Income tax expense	28,985	26,047	25,594
Net income	$ 54,958	$ 49,633	$ 48,195
Basic net income per common share, in dollars per share	$ 2.23	$ 2.02	$ 1.96
Diluted net income per common share, in dollars per share	$ 2.23	$ 2.02	$ 1.96