Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest income:
Loans, including fees	$ 127,041	$ 91,752
Investment securities:
Taxable	8,788	7,231
Tax-exempt	1,559	1,430
Federal funds sold and securities purchased under agreements to resell	660	573
Total interest income	138,048	100,986
Interest expense:
Deposits	6,913	2,497
Federal funds purchased and securities sold under agreements to repurchase	454	240
Other borrowings	1,708	887
Total interest expense	9,075	3,624
Net interest income	128,973	97,362
Provision for loan losses	2,454	3,707
Net interest income after provision for loan losses	126,519	93,655
Noninterest income:
Fees on deposit accounts	25,506	21,719
Mortgage banking income	4,948	5,569
Trust and investment services income	7,514	5,941
Recoveries on acquired loans	2,975	1,532
Other	2,575	1,674
Total noninterest income	43,518	36,435
Noninterest expense:
Salaries and employee benefits	62,465	48,886
Net occupancy expense	8,166	6,388
Information services expense	9,738	6,360
Furniture and equipment expense	4,626	3,794
OREO expense and loan related	1,661	2,142
Bankcard expense	3,654	2,770
Amortization of intangibles	3,413	2,507
Supplies, printing and postage expense	1,392	1,654
Professional fees	1,699	1,773
FDIC assessment and other regulatory charges	1,263	1,122
Advertising and marketing	736	559
Merger and branch consolidation related expenses	11,296	21,024
Other	6,317	5,744
Total noninterest expense	116,426	104,723
Earnings:
Income before provision for income taxes	53,611	25,367
Provision for income taxes	11,285	7,103
Net income	$ 42,326	$ 18,264
Earnings per common share:
Basic (in dollars per share)	$ 1.15	$ 0.63
Diluted (in dollars per share)	1.15	0.63
Dividends per common share (in dollars per share)	$ 0.33	$ 0.33
Weighted-average common shares outstanding:
Basic (in shares)	36,646	28,892
Diluted (in shares)	36,899	29,159