Investments in Servicing Related Assets, Geographic Concentration (Details)	Mar. 31, 2017	Dec. 31, 2016
Investment [Line Items]
Outstanding unpaid principal balance	100.00%	100.00%
California [Member]
Investment [Line Items]
Outstanding unpaid principal balance	12.40%	8.90%
New Jersey [Member]
Investment [Line Items]
Outstanding unpaid principal balance	8.20%	5.60%
Texas [Member]
Investment [Line Items]
Outstanding unpaid principal balance	5.60%	10.00%
Utah [Member]
Investment [Line Items]
Outstanding unpaid principal balance	5.50%
Florida [Member]
Investment [Line Items]
Outstanding unpaid principal balance	5.10%	6.70%
Virginia [Member]
Investment [Line Items]
Outstanding unpaid principal balance		5.90%
North Carolina [Member]
Investment [Line Items]
Outstanding unpaid principal balance		5.80%
Georgia [Member]
Investment [Line Items]
Outstanding unpaid principal balance		5.80%
Washington [Member]
Investment [Line Items]
Outstanding unpaid principal balance		5.50%
Colorado [Member]
Investment [Line Items]
Outstanding unpaid principal balance		5.20%
All Other [Member]
Investment [Line Items]
Outstanding unpaid principal balance	63.20%	40.60%