Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest income:
Loans, including fees	$ 131,834	$ 127,041
Investment securities:
Taxable	8,597	8,788
Tax-exempt	1,496	1,559
Federal funds sold and securities purchased under agreements to resell	1,463	660
Total interest income	143,390	138,048
Interest expense:
Deposits	16,645	6,913
Federal funds purchased and securities sold under agreements to repurchase	753	454
Other borrowings	2,725	1,708
Total interest expense	20,123	9,075
Net interest income	123,267	128,973
Provision for loan losses	1,488	2,454
Net interest income after provision for loan losses	121,779	126,519
Noninterest income:
Securities gains, net	541
Recoveries on acquired loans	1,867	2,975
Other	2,188	2,575
Total noninterest income	32,058	40,555
Noninterest expense:
Salaries and employee benefits	58,431	62,465
Net occupancy expense	7,199	8,166
Information services expense	9,009	9,738
Furniture and equipment expense	4,413	4,626
OREO expense and loan related	751	1,661
Amortization of intangibles	3,281	3,413
Supplies, printing and postage expense	1,504	1,392
Professional fees	2,240	1,699
FDIC assessment and other regulatory charges	1,535	1,263
Advertising and marketing	807	736
Merger and branch consolidation related expense	1,114	11,296
Other	7,955	7,008
Total noninterest expense	98,239	113,463
Earnings:
Income before provision for income taxes	55,598	53,611
Provision for income taxes	11,231	11,285
Net income	$ 44,367	$ 42,326
Earnings per common share:
Basic (in dollars per share)	$ 1.25	$ 1.15
Diluted (in dollars per share)	1.25	1.15
Dividends per common share (in dollars per share)	$ 0.38	$ 0.33
Weighted average common shares outstanding:
Basic (in shares)	35,445	36,646
Diluted (in shares)	35,619	36,899
Fees on deposit accounts
Noninterest income:
Noninterest income	$ 17,808	$ 22,543
Mortgage banking income
Noninterest income:
Noninterest income	2,385	4,948
Trust and investment services income
Noninterest income:
Noninterest income	$ 7,269	$ 7,514