Valuation Schedule of Fair Value Measurements (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | $ 1,831 | $ 11,839 |
Financial derivatives–liabilities, at fair value | (15,891) | (16,559) |
Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 1,459,452 | 1,540,296 |
Financial derivatives-assets, at fair value | 1,831 | 11,839 |
Total mortgage-backed securities and financial derivatives–assets, at fair value | 1,461,283 | 1,552,135 |
Financial derivatives–liabilities, at fair value | (15,891) | (16,559) |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | (50,413) | (16,933) |
Fair Value, Measurements, Recurring [Member] | TBA securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 338 | 794 |
Financial derivatives–liabilities, at fair value | (1,576) | (2,536) |
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 1,253 | 11,045 |
Financial derivatives–liabilities, at fair value | (14,315) | (6,193) |
Fair Value, Measurements, Recurring [Member] | Futures [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 240 | |
Financial derivatives–liabilities, at fair value | | (7,830) |
Fair Value, Measurements, Recurring [Member] | Agency RMBS [Member] | 15-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 165,605 | 137,531 |
Fair Value, Measurements, Recurring [Member] | Agency RMBS [Member] | 20-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 31,402 | 7,505 |
Fair Value, Measurements, Recurring [Member] | Agency RMBS [Member] | 30-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 1,106,247 | 1,273,514 |
Fair Value, Measurements, Recurring [Member] | Agency RMBS [Member] | Adjustable Rate Mortgages | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 40,422 | 18,243 |
Fair Value, Measurements, Recurring [Member] | Agency RMBS [Member] | Reverse mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 94,690 | 75,904 |
Fair Value, Measurements, Recurring [Member] | Agency RMBS [Member] | Interest-Only [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 11,801 | 16,366 |
Fair Value, Measurements, Recurring [Member] | Non-Agency RMBS [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 9,285 | 11,233 |
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
U.S. Treasury securities sold short, at fair value | (34,522) | (374) |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Financial derivatives-assets, at fair value | 240 | 0 |
Total mortgage-backed securities and financial derivatives–assets, at fair value | 240 | 0 |
Financial derivatives–liabilities, at fair value | 0 | (7,830) |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | 0 | (7,830) |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | TBA securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 0 | 0 |
Financial derivatives–liabilities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest Rate Swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 0 | 0 |
Financial derivatives–liabilities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Futures [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 240 | |
Financial derivatives–liabilities, at fair value | | (7,830) |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency RMBS [Member] | 15-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency RMBS [Member] | 20-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency RMBS [Member] | 30-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency RMBS [Member] | Adjustable Rate Mortgages | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency RMBS [Member] | Reverse mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Agency RMBS [Member] | Interest-Only [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Non-Agency RMBS [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | US Treasury Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
U.S. Treasury securities sold short, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 1,452,142 | 1,532,830 |
Financial derivatives-assets, at fair value | 1,591 | 11,839 |
Total mortgage-backed securities and financial derivatives–assets, at fair value | 1,453,733 | 1,544,669 |
Financial derivatives–liabilities, at fair value | (15,891) | (8,729) |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | (50,413) | (9,103) |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | TBA securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 338 | 794 |
Financial derivatives–liabilities, at fair value | (1,576) | (2,536) |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 1,253 | 11,045 |
Financial derivatives–liabilities, at fair value | (14,315) | (6,193) |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Futures [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 0 | |
Financial derivatives–liabilities, at fair value | | 0 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency RMBS [Member] | 15-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 165,605 | 137,531 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency RMBS [Member] | 20-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 31,402 | 7,505 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency RMBS [Member] | 30-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 1,106,247 | 1,273,514 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency RMBS [Member] | Adjustable Rate Mortgages | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 40,422 | 18,243 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency RMBS [Member] | Reverse mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 94,690 | 75,904 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Agency RMBS [Member] | Interest-Only [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 6,851 | 13,534 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Non-Agency RMBS [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 6,925 | 6,599 |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | US Treasury Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
U.S. Treasury securities sold short, at fair value | (34,522) | (374) |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 7,310 | 7,466 |
Financial derivatives-assets, at fair value | 0 | 0 |
Total mortgage-backed securities and financial derivatives–assets, at fair value | 7,310 | 7,466 |
Financial derivatives–liabilities, at fair value | 0 | 0 |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | TBA securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 0 | 0 |
Financial derivatives–liabilities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest Rate Swap [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 0 | 0 |
Financial derivatives–liabilities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Futures [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Financial derivatives-assets, at fair value | 0 | |
Financial derivatives–liabilities, at fair value | | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency RMBS [Member] | 15-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency RMBS [Member] | 20-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency RMBS [Member] | 30-year fixed rate mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency RMBS [Member] | Adjustable Rate Mortgages | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency RMBS [Member] | Reverse mortgages [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Agency RMBS [Member] | Interest-Only [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 4,950 | 2,832 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Non-Agency RMBS [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Mortgage-backed securities, at fair value | 2,360 | 4,634 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | US Treasury Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
U.S. Treasury securities sold short, at fair value | $ 0 | $ 0 |