Liability for Losses Under Representations and Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
During the year:
Balance at beginning of year	$ 21,155	$ 20,053	$ 19,067
Provision for losses on loans sold resulting from sales of loans	8,377	5,824	5,890
Provision for losses on loans sold reduction in liability due to change in estimate	(7,877)	(4,672)	(4,301)
Losses incurred, net	(209)	(50)	(603)
Balance at end of year	21,446	21,155	$ 20,053
Unpaid principal balance of loans subject to representations and warranties at end of year	$ 177,611,568	$ 137,849,704