Liability for Losses Under Representations and Warranties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
During the year:
Balance at beginning of period	$ 21,446	$ 21,155
Provision for losses on loans sold resulting from sales of loans	3,712	1,067
Provision for losses on loans sold reduction in liability due to change in estimate	(1,676)	(4,210)
Losses incurred, net	(280)	(30)
Balance at end of period	23,202	17,982
Unpaid principal balance of loans subject to representations and warranties at end of year	$ 186,517,598	$ 133,698,782