Condensed Consolidated Statements of (Loss) Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Interest income:
Loans, including fees	$ 167,707	$ 135,388	$ 300,741	$ 267,222
Investment securities:
Taxable	10,920	9,551	22,835	18,148
Tax-exempt	1,505	1,617	2,904	3,113
Federal funds sold, securities purchased under agreements to resell and interest-bearing deposits with banks	432	3,426	1,884	4,889
Total interest income	180,564	149,982	328,364	293,372
Interest expense:
Deposits	12,624	17,393	27,061	34,038
Federal funds purchased and securities sold under agreements to repurchase	391	673	1,006	1,426
Corporate and subordinated debentures	1,971	1,450	3,162	2,935
Other borrowings	3,021	3,287	6,564	4,527
Total interest expense	18,007	22,803	37,793	42,926
Net interest income	162,557	127,179	290,571	250,446
Provision for loan losses	151,474	3,704	188,007	5,192
Net interest income after provision for loan losses	11,083	123,475	102,564	245,254
Noninterest income:
Securities gains, net		1,709		2,250
Recoveries on acquired loans		1,347		3,214
Other	2,092	1,933	5,554	4,137
Total noninterest income	54,347	37,618	98,479	69,676
Noninterest expense:
Salaries and employee benefits	81,720	58,547	142,698	116,978
Occupancy expense	15,959	11,849	28,246	23,461
Information services expense	12,155	8,671	21,462	17,680
OREO expense and loan related	1,107	881	1,694	1,632
Pension plan termination expense		9,526		9,526
Amortization of intangibles	4,665	3,268	7,672	6,549
Supplies, printing and postage expense	1,610	1,495	3,115	2,999
Professional fees	2,848	2,781	5,342	5,021
FDIC assessment and other regulatory charges	2,403	1,455	4,461	2,990
Advertising and marketing	531	959	1,345	1,766
Merger and branch consolidation related expense	40,279	2,078	44,408	3,058
Other	11,835	7,897	21,917	15,986
Total noninterest expense	175,112	109,407	282,360	207,646
(Loss) earnings:
(Loss) income before provision for income taxes	(109,682)	51,686	(81,317)	107,284
(Benefit of) provision for income taxes	(24,747)	10,226	(20,492)	21,457
Net (loss) income	$ (84,935)	$ 41,460	$ (60,825)	$ 85,827
(Loss) earnings per common share:
Basic (in dollars per share)	$ (1.96)	$ 1.18	$ (1.58)	$ 2.43
Diluted (in dollars per share)	$ (1.96)	$ 1.17	$ (1.58)	$ 2.42
Weighted average common shares outstanding:
Basic (in shares)	43,318	35,089	38,439	35,268
Diluted (in shares)	43,318	35,300	38,439	35,461
Fees on deposit accounts
Noninterest income:
Noninterest income	$ 16,679	$ 18,741	$ 34,820	$ 36,549
Mortgage banking income
Noninterest income:
Noninterest income	18,371	5,307	33,018	7,692
Trust and investment services income
Noninterest income:
Noninterest income	7,138	7,720	14,527	14,989
Correspondent banking and capital market income
Noninterest income:
Noninterest income	$ 10,067	$ 861	$ 10,560	$ 845