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, 2020	Mar. 31, 2019
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance, Goodwill	$ 148,353	$ 128,177
Ending balance, Goodwill	148,353	128,177
Amortization	(1,893)	(1,773)
Core Deposits
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	29,111	30,360
Amortization	(1,826)	(1,706)
Ending balance	27,285	28,654
Accumulated amortization	$ 28,181	$ 20,592
Weighted average remaining amortization period	6 years 3 months 18 days	6 years 7 months 6 days
Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 2,791	$ 3,059
Amortization	(67)	(67)
Ending balance	2,724	2,992
Accumulated amortization	$ 492	$ 224
Weighted average remaining amortization period	10 years 2 months 12 days	11 years 2 months 12 days