Commercial Mortgage Residual Interests Schedule of Amounts Recognized as Unrealized Gains and/or Losses Recorded as Other Comprehensive Income and Other Than Temporary Valuation Impairments Recorded in Earnings (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Unrealized gains (losses)	$ (4,561)	$ 116	$ (4,454)	$ (268)
Other than temporary valuation impairment	$ 5,978	$ 53	$ 6,830	$ 481