Unfunded Loan Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Credit Loss [Abstract]
Contractual obligation	$ 457,000
Allowance
Beginning balance	110,044	$ 2,481
Provision/New commitments - net	40,197	49,561
Other provision items	(3,994)	3,982
Transfer - funded loans	(126,880)	(142,075)
Ending balance	19,367	29,707
Unfunded Commitments
Beginning balance	1,673,018	1,910,603
Provision/New commitments - net	843,161	834,946
Other provision items	0	0
Transfer - funded loans	(2,058,726)	(2,295,742)
Ending balance	457,453	449,807
Cumulative Effect, Period Of Adoption, Adjustment
Allowance
Beginning balance	0	115,758
Unfunded Commitments
Beginning balance	0	0
Cumulative Effect, Period Of Adoption, Adjusted Balance
Allowance
Beginning balance	110,044	118,239
Unfunded Commitments
Beginning balance	$ 1,673,018	$ 1,910,603