Goodwill, Core Deposit Intangible and Other Intangible Assets - Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance, Goodwill	$ 148,353	$ 148,353
Ending balance, Goodwill	148,353	148,353
Amortization	(1,749)	(1,893)
Core Deposits
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	21,809	29,111
Amortization	(1,683)	(1,826)
Ending balance	20,126	27,285
Accumulated amortization	$ 33,340	$ 28,181
Weighted average remaining amortization period	5 years 4 months 24 days	6 years 3 months 18 days
Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 2,469	$ 2,791
Amortization	(66)	(67)
Ending balance	2,403	2,724
Accumulated amortization	$ 813	$ 492
Weighted average remaining amortization period	9 years	10 years 2 months 12 days