Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest revenue:
Loans, including fees	$ 476,039	$ 420,383	$ 315,050
Investment securities:
Taxable	69,920	73,496	70,172
Tax exempt	4,564	4,189	2,216
Deposits in banks and short-term investments	2,183	2,012	2,282
Total interest revenue	552,706	500,080	389,720
Interest expense:
Deposits	66,856	39,543	17,062
Short-term borrowings	838	1,112	352
Federal Home Loan Bank advances	2,697	6,345	6,095
Long-term debt	12,921	14,330	10,226
Total interest expense	83,312	61,330	33,735
Net interest revenue	469,394	438,750	355,985
Provision for credit losses	13,150	9,500	3,800
Net interest revenue after provision for credit losses	456,244	429,250	352,185
Noninterest income:
Brokerage fees	6,150	5,191	4,633
Gains from other loan sales, net	6,867	9,277	10,493
Securities (losses) gains, net	(1,021)	(656)	42
Other	28,775	24,142	16,477
Total noninterest income	104,713	92,961	88,260
Total revenue	560,957	522,211	440,445
Noninterest expenses:
Salaries and employee benefits	196,440	181,015	153,098
Occupancy	23,350	22,781	20,344
Communications and equipment	24,613	21,277	19,660
FDIC assessments and other regulatory charges	4,901	8,491	6,534
Professional fees	17,028	15,540	12,074
Lending and loan servicing expense	9,416	8,697	7,512
Outside services - electronic banking	7,020	6,623	6,487
Postage, printing and supplies	6,370	6,416	5,952
Advertising and public relations	6,170	5,991	4,242
Amortization of intangibles	4,938	6,846	4,845
Merger-related and other charges	6,907	5,414	13,901
Other	15,092	17,194	12,962
Total noninterest expenses	322,245	306,285	267,611
Income before income taxes	238,712	215,926	172,834
Income tax expense	52,991	49,815	105,013
Net income	185,721	166,111	67,821
Net income available to common shareholders	$ 184,346	$ 164,927	$ 67,250
Income per common share:
Basic (in dollars per share)	$ 2.31	$ 2.07	$ 0.92
Diluted (in dollars per share)	$ 2.31	$ 2.07	$ 0.92
Weighted average common shares outstanding:
Basic (in shares)	79,700	79,662	73,247
Diluted (in shares)	79,708	79,671	73,259
Service charges and fees
Noninterest income:
Service charges and other related fees	$ 36,797	$ 35,997	$ 38,295
Mortgage loan gains and related fees
Noninterest income:
Service charges and other related fees	$ 27,145	$ 19,010	$ 18,320