Loans and Allowance for Credit Losses for Loans - Summary of Provision for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Receivables [Abstract]
Provision for credit losses for loans	$ 33,851	$ 7,856
Provision for unfunded credit commitments	73	144
Total provision for credit losses for loans	$ 33,924	$ 8,000