Loans - Summary of Allowance for Loan Losses by Portfolio Class and Category (Details) - Portfolio loans, net - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Dec. 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 21, 2021
Allowance for Loan Losses [Roll Forward]
Beginning Balance		$ 128,185	$ 110,270	$ 136,671	$ 43,288
Initial allowance on acquired PCD loans						$ 7,006
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	$ 28,387
Provision for credit losses	(1,680)
Provision for Loan, Lease, and Other Losses		18,755	14,027	16,785	54,113
Charge-offs		(4,251)	(2,584)	(12,558)	(6,552)
Recoveries		2,401	1,557	4,192	5,714
Ending Balance	43,288	152,096	123,270	152,096	123,270
Commercial and industrial
Allowance for Loan Losses [Roll Forward]
Beginning Balance		53,351	50,139	58,812	27,455
Initial allowance on acquired PCD loans						1,077
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	6,494
Provision for credit losses	0
Provision for Loan, Lease, and Other Losses		9,836	8,929	8,538	27,688
Charge-offs		(2,829)	(2,006)	(8,019)	(5,372)
Recoveries		452	808	1,479	1,605
Ending Balance	27,455	61,887	57,870	61,887	57,870
CRE - investor owned
Allowance for Loan Losses [Roll Forward]
Beginning Balance		36,003	25,019	32,062	5,935
Initial allowance on acquired PCD loans						3,651
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	10,726
Provision for credit losses	(5)
Provision for Loan, Lease, and Other Losses		1,475	4,869	7,715	10,692
Charge-offs		(117)	(272)	(2,489)	(498)
Recoveries		1,623	55	1,696	2,821
Ending Balance	5,935	42,635	29,671	42,635	29,671
CRE - owner occupied
Allowance for Loan Losses [Roll Forward]
Beginning Balance		15,564	11,088	17,012	4,873
Initial allowance on acquired PCD loans						1,504
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	2,598
Provision for credit losses	(57)
Provision for Loan, Lease, and Other Losses		1,909	(1,854)	686	1,740
Charge-offs		(259)	(30)	(503)	(30)
Recoveries		15	268	34	348
Ending Balance	4,873	18,733	9,472	18,733	9,472
Construction and land development
Allowance for Loan Losses [Roll Forward]
Beginning Balance		11,632	15,962	21,413	2,611
Initial allowance on acquired PCD loans						37
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	5,183
Provision for credit losses	(217)
Provision for Loan, Lease, and Other Losses		2,215	2,873	(7,833)	11,220
Charge-offs		(3)	0	(3)	(31)
Recoveries		171	83	438	152
Ending Balance	2,611	14,052	18,918	14,052	18,918
Residential real estate
Allowance for Loan Losses [Roll Forward]
Beginning Balance		4,677	6,333	4,585	1,280
Initial allowance on acquired PCD loans						0
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	3,470
Provision for credit losses	(1,401)
Provision for Loan, Lease, and Other Losses		5,271	(1,132)	5,374	1,623
Charge-offs		(840)	(173)	(1,155)	(327)
Recoveries		115	303	419	686
Ending Balance	1,280	9,223	5,331	9,223	5,331
Other
Allowance for Loan Losses [Roll Forward]
Beginning Balance		6,958	1,729	2,787	1,134
Initial allowance on acquired PCD loans						$ 737
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(84)
Provision for credit losses	0
Provision for Loan, Lease, and Other Losses		(1,951)	342	2,305	1,150
Charge-offs		(203)	(103)	(389)	(294)
Recoveries		25	40	126	102
Ending Balance	$ 1,134	$ 5,566	$ 2,008	$ 5,566	$ 2,008