Premises and Equipment - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense		$ 7,800	$ 7,800	$ 6,600
Net gain on sale of long-lived assets	$ 2,300	$ (825)	$ (69)	$ (1,627)
Disposal expenses	801
Leasehold improvements
Property, Plant and Equipment [Line Items]
Impairment loss	$ 150