Loans and Allowance for Credit Losses for Loans - Summary of Provision for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Provision for loan losses	$ 123,922	$ 25,809	$ 31,661
Provision for unfunded credit commitments	1,165	(1,591)	840
Total provision for credit losses for loans	$ 125,087	$ 24,218	$ 32,501