Loans and Allowance for Credit Losses for Loans - Summary of Provision for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Receivables [Abstract]
Provision for loan losses	$ 41,025	$ 3,706	$ 74,876	$ 11,562
Provision for unfunded credit commitments	90	(1,606)	163	(1,462)
Total provision for credit losses for loans	$ 41,115	$ 2,100	$ 75,039	$ 10,100