Annual report pursuant to Section 13 and 15(d)

Credit Facilities - Senior Credit Facilities (Details)

v3.10.0.1
Credit Facilities - Senior Credit Facilities (Details) - Senior Secured Revolving Credit Facility [Member]
 12 Months Ended
Dec. 31, 2018
USD ($)
debt_instrument
Line of Credit Facility [Line Items]  
Number of revolving credit facilities | debt_instrument 2
Unamortized issuance costs $ 8,000,000
Default underlying financings (percent) 50.00%
LIBOR [Member] | Credit Default Option [Member]  
Line of Credit Facility [Line Items]  
Basis spread on variable rate (as a percent) 2.00%
Rep-Based Facility [Member]  
Line of Credit Facility [Line Items]  
Principal amount $ 250,000,000
Availability fee percentage 0.60%
Rep-Based Facility [Member] | U.S. Federal Government [Member]  
Line of Credit Facility [Line Items]  
Applicable valuation percentages 85.00%
Rep-Based Facility [Member] | Institutional [Member]  
Line of Credit Facility [Line Items]  
Applicable valuation percentages 80.00%
Rep-Based Facility [Member] | LIBOR [Member]  
Line of Credit Facility [Line Items]  
Basis spread on variable rate (as a percent) 1.40%
Fixed interest rate 1.85%
Rep-Based Facility [Member] | Federal Funds Rate [Member]  
Line of Credit Facility [Line Items]  
Basis spread on variable rate (as a percent) 0.40%
Fixed interest rate 0.85%
Approval-Based Facility [Member]  
Line of Credit Facility [Line Items]  
Principal amount $ 200,000,000
Approval-Based Facility [Member] | Certain Approved Existing Financing [Member]  
Line of Credit Facility [Line Items]  
Applicable valuation percentages 85.00%
Approval-Based Facility [Member] | Others as Prescribed by Administrative Agent [Member]  
Line of Credit Facility [Line Items]  
Applicable valuation percentages 67.00%
Approval-Based Facility [Member] | LIBOR [Member]  
Line of Credit Facility [Line Items]  
Basis spread on variable rate (as a percent) 1.50%
Fixed interest rate 2.00%
Approval-Based Facility [Member] | Federal Funds Rate [Member]  
Line of Credit Facility [Line Items]  
Basis spread on variable rate (as a percent) 0.50%
Fixed interest rate 1.00%