Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Interest income:
Loans, including fees	$ 77,254	$ 78,848
Investment securities:
Taxable	4,793	3,661
Tax-exempt	1,016	1,078
Federal funds sold and securities purchased under agreements to resell	752	411
Total interest income	83,815	83,998
Interest expense:
Deposits	1,600	2,003
Federal funds purchased and securities sold under agreements to repurchase	144	96
Other borrowings	469	850
Total interest expense	2,213	2,949
Net interest income	81,602	81,049
Provision for loan losses	2,557	818
Net interest income after provision for loan losses	79,045	80,231
Noninterest income:
Fees on deposit accounts	20,125	16,492
Mortgage banking income	4,198	6,626
Trust and investment services income	4,785	4,934
Securities losses, net	122
Amortization of FDIC indemnification assets	(1,475)	(3,207)
Other	2,286	1,660
Total noninterest income	30,041	26,505
Noninterest expense:
Salaries and employee benefits	41,432	40,987
Net occupancy expense	5,359	5,237
Information services expense	5,034	3,958
Furniture and equipment expense	2,851	3,145
OREO expense and loan related	1,774	3,014
Bankcard expense	2,879	1,980
Amortization of intangibles	1,904	2,016
Supplies, printing and postage expense	1,808	1,612
Professional fees	1,329	1,409
FDIC assessment and other regulatory charges	1,144	1,184
Advertising and marketing	645	855
Branch and conversion related expense	958
Other	4,913	5,088
Total noninterest expense	72,030	70,485
Earnings:
Income before provision for income taxes	37,056	36,251
Provision for income taxes	12,562	12,325
Net income	24,494	23,926
Net income	$ 24,494	$ 23,926
Earnings per common share:
Basic (in dollars per share)	$ 1.02	$ 1.00
Diluted (in dollars per share)	1.01	0.99
Dividends per common share (in dollars per share)	$ 0.28	$ 0.23
Weighted-average common shares outstanding:
Basic (in shares)	23,969	23,943
Diluted (in shares)	24,191	24,201