Quarterly report pursuant to Section 13 or 15(d)

Available-for-Sale Securities, at Fair Value Other than Temporary Impairment, Credit Losses Recognized in Earnings (Details)

v3.8.0.1
Available-for-Sale Securities, at Fair Value Other than Temporary Impairment, Credit Losses Recognized in Earnings (Details)
$ in Thousands
3 Months Ended
Mar. 31, 2018
USD ($)
position
Mar. 31, 2017
USD ($)
position
Available-for-sale Securities [Abstract]    
Other-than-temporary impairment losses $ (94) $ 0
Other than Temporary Impairment Losses, Investments, Number, Available-for-sale Securities | position 1 0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Market Value $ 116,784  
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Weighted Average Cumulative Losses 5.70%  
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Weighted Average Three-Month Prepayment Speed 0.054  
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Delinquency Rate 22.00%  
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Weighted Average FICO Score 658  
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]    
Cumulative credit loss at beginning of period $ (6,395) $ (5,606)
Other-than-temporary impairments not previously recognized 0 0
Increases related to other-than-temporary impairments on securities with previously recognized other-than-temporary impairments (94) 0
Decreases related to other-than-temporary impairments on securities paid down 0 0
Decreases related to other-than-temporary impairments on securities sold 0 0
Cumulative credit loss at end of period $ (6,489) $ (5,606)