Derivative Financial Instruments - Summary of TBA Contracts - 30 Year [Member]	Sep. 30, 2016 USD ($)
Derivatives, Fair Value [Line Items]
Notional Amount	$ (146,800,000)
Cost Basis	(158,450,000)
Market Value Of TBA Contract	(158,690,000)
Liabilities, at Fair Value	240
4.0% [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	(100,000,000)
Cost Basis	(107,219,000)
Market Value Of TBA Contract	(107,422,000)
Liabilities, at Fair Value	203,000
4.5% [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	(46,800,000)
Cost Basis	(51,231,000)
Market Value Of TBA Contract	(51,268,000)
Liabilities, at Fair Value	$ 37,000