Commitments and Contingencies - Commitments and Letters of Credit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Commitment And Contingencies [Line Items]
Total Commitments	$ 2,274,847	$ 1,990,845
Standby letters of credit
Commitment And Contingencies [Line Items]
Total Commitments	89,095	80,040
Commitments to extend credit
Commitment And Contingencies [Line Items]
Total Commitments	$ 2,185,752	$ 1,910,805