Certain Transfers of Financial Assets Certain Transfers of Financial Assets (Details 4) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Transfers and Servicing [Abstract]
50 bp adverse change in prepayment speed	$ (8,338)	$ (10,768)
100 bp adverse change in prepayment speed	$ (10,091)	$ (17,965)