Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest income:
Loans, including fees	$ 77,154	$ 79,406	$ 154,408	$ 158,254
Investment securities:
Taxable	4,477	3,822	9,270	7,484
Tax-exempt	992	1,072	2,008	2,150
Federal funds sold and securities purchased under agreements to resell	756	464	1,508	875
Total interest income	83,379	84,764	167,194	168,763
Interest expense:
Deposits	1,368	1,737	2,969	3,740
Federal funds purchased and securities sold under agreements to repurchase	137	105	281	201
Other borrowings	475	646	944	1,497
Total interest expense	1,980	2,488	4,194	5,438
Net interest income	81,399	82,276	163,000	163,325
Provision for loan losses	2,727	3,144	5,286	3,963
Net interest income after provision for loan losses	78,672	79,132	157,714	159,362
Noninterest income:
Fees on deposit accounts	21,539	17,699	41,663	34,192
Mortgage banking income	5,620	7,089	9,818	13,715
Trust and investment services income	4,911	5,051	9,697	9,985
Securities losses, net			122
Amortization of FDIC indemnification assets	(4,427)	(2,042)	(5,901)	(5,249)
Other	4,475	2,285	6,761	3,945
Total noninterest income	32,118	30,082	62,160	56,588
Noninterest expense:
Salaries and employee benefits	40,537	39,754	81,969	80,741
Net occupancy expense	5,541	5,046	10,900	10,283
Information services expense	5,083	4,382	10,117	8,340
Furniture and equipment expense	3,072	2,762	5,923	5,907
OREO expense and loan related	874	2,019	2,648	5,033
Bankcard expense	3,040	2,285	5,919	4,265
Amortization of intangibles	1,892	1,964	3,795	3,980
Supplies, printing and postage expense	1,757	1,430	3,565	3,042
Professional fees	1,576	1,585	2,906	2,994
FDIC assessment and other regulatory charges	1,017	1,253	2,161	2,437
Advertising and marketing	858	1,009	1,502	1,864
Branch and conversion related expense	1,573	2,237	2,531	2,237
Other	7,034	5,803	11,947	10,891
Total noninterest expense	73,854	71,529	145,883	142,014
Earnings:
Income before provision for income taxes	36,936	37,685	73,991	73,936
Provision for income taxes	12,420	12,813	24,981	25,138
Net income	24,516	24,872	49,010	48,798
Net income	$ 24,516	$ 24,872	$ 49,010	$ 48,798
Earnings per common share:
Basic (in dollars per share)	$ 1.02	$ 1.04	$ 2.04	$ 2.04
Diluted (in dollars per share)	1.01	1.03	2.02	2.02
Dividends per common share (in dollars per share)	$ 0.30	$ 0.24	$ 0.58	$ 0.47
Weighted-average common shares outstanding:
Basic (in shares)	23,995	23,981	23,977	23,947
Diluted (in shares)	24,237	24,258	24,205	24,214