Valuation Schedule of Fair Value Measurements (Details) (USD $) | 9 Months Ended | 12 Months Ended |
Sep. 30, 2014 | Dec. 31, 2013 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | $1,368,092,000 | | $1,326,036,000 | |
Financial derivatives-assets, at fair value | 8,439,000 | [1] | 34,963,000 | [1] |
Reverse repurchase agreements | 2,484,000 | [1] | 0 | |
U.S. Treasury securities sold short, at fair value | 2,483,000 | | 0 | |
Financial derivatives-liabilities, at fair value | -2,850,000 | [1] | -1,069,000 | [1] |
Fair Value Level 1 To Level 2 To Level 3 Transfers Amount | 0 | | 0 | |
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 | 0 | | 0 | |
Reverse repurchase agreements | 0 | | ' | |
Total mortgage-backed securities, financial derivatives–assets, and reverse repurchase agreements, at fair value | 0 | | 0 | |
Financial derivatives-liabilities, at fair value | 0 | | 0 | |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | 0 | | ' | |
Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 1,320,118,000 | | 1,281,828,000 | |
Financial derivatives-assets, at fair value | 8,439,000 | | 34,963,000 | |
Reverse repurchase agreements | 2,484,000 | | ' | |
Total mortgage-backed securities, financial derivatives–assets, and reverse repurchase agreements, at fair value | 1,331,041,000 | | 1,316,791,000 | |
Financial derivatives-liabilities, at fair value | -2,850,000 | | -1,069,000 | |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | -5,333,000 | | ' | |
Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 47,974,000 | | 44,208,000 | |
Financial derivatives-assets, at fair value | 0 | | 0 | |
Reverse repurchase agreements | 0 | | ' | |
Total mortgage-backed securities, financial derivatives–assets, and reverse repurchase agreements, at fair value | 47,974,000 | | 44,208,000 | |
Financial derivatives-liabilities, at fair value | 0 | | 0 | |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | 0 | | ' | |
Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 1,368,092,000 | | 1,326,036,000 | |
Financial derivatives-assets, at fair value | 8,439,000 | | 34,963,000 | |
Reverse repurchase agreements | 2,484,000 | | ' | |
Total mortgage-backed securities, financial derivatives–assets, and reverse repurchase agreements, at fair value | 1,379,015,000 | | 1,360,999,000 | |
Financial derivatives-liabilities, at fair value | -2,850,000 | | -1,069,000 | |
Total U.S. Treasury securities and financial derivatives-liabilities, at fair value | -5,333,000 | | ' | |
Non-Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 33,732,000 | | 30,681,000 | |
Non-Agency RMBS [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 | |
Non-Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | 0 | |
Non-Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 33,732,000 | | 30,681,000 | |
Non-Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 33,732,000 | | 30,681,000 | |
Residential Mortgage Backed Securities [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 1,368,092,000 | | 1,326,036,000 | |
US Treasury Securities [Member] | Level 1 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
U.S. Treasury securities sold short, at fair value | 0 | | ' | |
US Treasury Securities [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
U.S. Treasury securities sold short, at fair value | -2,483,000 | | ' | |
US Treasury Securities [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
U.S. Treasury securities sold short, at fair value | 0 | | ' | |
US Treasury Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
U.S. Treasury securities sold short, at fair value | -2,483,000 | | ' | |
15-year fixed rate mortgages [Member] | Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 143,357,000 | | 183,872,000 | |
15-year fixed rate mortgages [Member] | Agency RMBS [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 | |
15-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 143,357,000 | | 183,872,000 | |
15-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | 0 | |
15-year fixed rate mortgages [Member] | Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 143,357,000 | | 183,872,000 | |
20-year fixed rate mortgages [Member] | Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 10,662,000 | | ' | |
20-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 1 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | ' | |
20-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 10,662,000 | | ' | |
20-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | ' | |
20-year fixed rate mortgages [Member] | Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 10,662,000 | | ' | |
30-year fixed rate mortgages [Member] | Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 1,098,761,000 | | 1,043,573,000 | |
30-year fixed rate mortgages [Member] | Agency RMBS [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 | |
30-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 1,098,761,000 | | 1,043,573,000 | |
30-year fixed rate mortgages [Member] | Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | 0 | |
30-year fixed rate mortgages [Member] | Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 1,098,761,000 | | 1,043,573,000 | |
Adjustable Rate Mortgages | Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 46,121,000 | | 46,115,000 | |
Adjustable Rate Mortgages | Agency RMBS [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 | |
Adjustable Rate Mortgages | Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 46,121,000 | | 46,115,000 | |
Adjustable Rate Mortgages | Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | 0 | |
Adjustable Rate Mortgages | Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 46,121,000 | | 46,115,000 | |
Reverse mortgages [Member] | Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 21,217,000 | | 8,268,000 | |
Reverse mortgages [Member] | Agency RMBS [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 | |
Reverse mortgages [Member] | Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 21,217,000 | | 8,268,000 | |
Reverse mortgages [Member] | Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | 0 | |
Reverse mortgages [Member] | Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 21,217,000 | | 8,268,000 | |
Interest-Only [Member] | Agency RMBS [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 14,242,000 | | 13,527,000 | |
Interest-Only [Member] | Agency RMBS [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 | |
Interest-Only [Member] | Agency RMBS [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 0 | | 0 | |
Interest-Only [Member] | Agency RMBS [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 14,242,000 | | 13,527,000 | |
Interest-Only [Member] | Agency RMBS [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Mortgage-backed securities, at fair value | 14,242,000 | | 13,527,000 | |
Interest Rate Swap [Member] | Level 1 [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 | |
Interest Rate Swap [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-assets, at fair value | 8,042,000 | | 32,700,000 | |
Financial derivatives-liabilities, at fair value | -2,333,000 | | -956,000 | |
Interest Rate Swap [Member] | Level 3 [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 | |
Interest Rate Swap [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-assets, at fair value | 8,042,000 | | 32,700,000 | |
Financial derivatives-liabilities, at fair value | -2,333,000 | | -956,000 | |
Interest Rate Swap [Member] | Derivative Financial Instruments, Assets [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-assets, at fair value | 8,042,000 | | 32,700,000 | |
Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-liabilities, at fair value | -2,333,000 | | -956,000 | |
Interest Rate Swaption [Member] | Level 1 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-liabilities, at fair value | 0 | | 0 | |
Interest Rate Swaption [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-liabilities, at fair value | -25,000 | | -85,000 | |
Interest Rate Swaption [Member] | Level 3 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-liabilities, at fair value | 0 | | 0 | |
Interest Rate Swaption [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-liabilities, at fair value | -25,000 | | -85,000 | |
Interest Rate Swaption [Member] | Derivative Financial Instruments, Liabilities [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-liabilities, at fair value | -25,000 | | -85,000 | |
TBA securities [Member] | Level 1 [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 | |
TBA securities [Member] | Level 2 [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-assets, at fair value | 397,000 | | 2,263,000 | |
Financial derivatives-liabilities, at fair value | -492,000 | | -28,000 | |
TBA securities [Member] | Level 3 [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 | |
TBA securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | ' | | ' | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | | ' | |
Financial derivatives-assets, at fair value | 397,000 | | 2,263,000 | |
Financial derivatives-liabilities, at fair value | ($492,000) | | ($28,000) | |
|
[1] | In the Company's Consolidated Balance Sheet, all balances associated with the repurchase agreements and financial derivatives are presented on a gross basis. |