CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INTEREST INCOME
Loans	$ 485,663	$ 415,410	$ 251,027
Investment securities and other interest-earning assets	40,444	33,013	18,978
Total interest income	526,107	448,423	270,005
INTEREST EXPENSE
Deposits	58,297	37,653	13,371
FHLB advances and other borrowings	9,829	11,343	4,411
Subordinated debentures	10,680	6,716	4,721
Total interest expense	78,806	55,712	22,503
Net interest income before provision for credit losses	447,301	392,711	247,502
Provision for credit losses	5,719	8,253	8,432
Net interest income after provision for credit losses	441,582	384,458	239,070
NONINTEREST INCOME
Loan servicing fees	1,840	1,445	787
Earnings on bank-owned life insurance	3,486	3,427	2,279
Net gain from sales of loans	6,642	10,759	12,468
Net gain from sales of investment securities	8,571	1,399	2,737
Other income	4,486	3,641	5,680
Total noninterest income	35,236	31,027	31,114
NONINTEREST EXPENSE
Compensation and benefits	139,187	129,886	84,138
Premises and occupancy	30,758	24,544	14,742
Data processing	12,301	13,412	8,206
Other real estate owned operations, net	160	4	72
FDIC insurance premiums	764	3,002	2,151
Legal, audit and professional expense	12,869	10,040	6,101
Marketing expense	6,402	6,151	4,436
Office, telecommunications and postage expense	4,826	5,312	3,117
Loan expense	4,079	3,370	3,299
Deposit expense	15,266	9,916	6,240
Merger-related expense	656	18,454	21,002
CDI amortization	17,245	13,594	6,144
Other expense	14,552	12,220	8,310
Total noninterest expense	259,065	249,905	167,958
INCOME BEFORE INCOME TAXES	217,753	165,580	102,226
Income tax	58,035	42,240	42,126
NET INCOME	$ 159,718	$ 123,340	$ 60,100
EARNINGS PER SHARE
Basic (in dollars per share)	$ 2.62	$ 2.29	$ 1.59
Diluted (in dollars per share)	$ 2.60	$ 2.26	$ 1.56
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (in shares)	60,339,714	53,963,047	37,705,556
Diluted (in shares)	60,692,281	54,613,057	38,511,261
Service charges on deposit accounts
NONINTEREST INCOME
Noninterest income	$ 5,769	$ 5,128	$ 3,273
Other service fee income
NONINTEREST INCOME
Noninterest income	1,438	902	1,847
Debit card interchange fee income
NONINTEREST INCOME
Noninterest income	$ 3,004	$ 4,326	$ 2,043