Liability for Losses Under Representations and Warranties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
During the year:
Balance at beginning of quarter	$ 21,155	$ 20,053
Provision for losses on mortgage loans sold resulting from sales of mortgage loans	1,067	1,492
Provision for losses on mortgage loans sold reduction in liability due to change in estimate	(4,210)	(1,113)
Incurred losses, net	(30)	(3)
Balance at end of quarter	17,982	20,429
Unpaid principal balance of mortgage loans subject to representations and warranties at end of quarter	$ 133,698,782	$ 127,056,220