Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest income:
Loans, including fees	$ 315,574	$ 319,882	$ 268,596
Investment securities:
Taxable	16,110	15,758	11,073
Tax-exempt	4,300	4,589	4,773
Federal funds sold and securities purchased under agreements to resell	2,117	1,793	1,906
Total interest income	338,101	342,022	286,348
Interest expense:
Deposits	7,344	9,301	8,489
Federal funds purchased and securities sold under agreements to repurchase	395	357	426
Other borrowings	2,589	6,004	4,072
Total interest expense	10,328	15,662	12,987
Net interest income	327,773	326,360	273,361
Provision for loan losses	5,864	6,590	1,886
Net interest income after provision for loan losses	321,909	319,770	271,475
Noninterest income:
Fees on deposit accounts	74,479	69,291	54,798
Mortgage banking income	21,761	16,170	9,149
Trust and investment services income	20,117	18,344	12,661
Securities losses, net		2
Total other-than-temporary impairment losses	(489)
Amortization of FDIC indemnification assets	(8,587)	(21,895)	(29,535)
Other	8,274	12,788	6,647
Total noninterest income	115,555	94,696	53,720
Noninterest expense:
Salaries and employee benefits	161,304	158,432	122,096
Net occupancy expense	21,105	22,459	17,590
Information services expense	17,810	15,844	14,470
Furniture and equipment expense	11,233	13,271	12,112
OREO expense and loan related	9,595	11,833	13,727
Bankcard expense	9,320	8,563	6,550
Amortization of intangibles	8,324	8,320	6,081
Branch acquisition and consolidation expense	6,945
Supplies, printing and postage expense	5,919	6,937	4,891
Professional fees	5,533	4,960	4,210
FDIC assessment and other regulatory charges	4,714	5,432	5,034
Advertising and marketing	3,838	4,156	4,532
Merger expense		23,940	22,534
Other	21,449	18,891	16,794
Total noninterest expense	287,089	303,038	250,621
Earnings:
Income before provision for income taxes	150,375	111,428	74,574
Provision for income taxes	50,902	35,991	25,355
Net income	99,473	75,437	49,219
Preferred stock dividends		1,073	1,354
Net income	$ 99,473	$ 74,364	$ 47,865
Earnings per common share:
Basic (in dollars per share)	$ 4.15	$ 3.11	$ 2.41
Diluted (in dollars per share)	4.11	3.08	2.38
Dividends per common share (in dollars per share)	$ 0.98	$ 0.82	$ 0.74
Weighted-average common shares outstanding:
Basic (in shares)	23,966	23,897	19,866
Diluted (in shares)	24,224	24,154	20,077