Derivatives and other Hedging Instruments - Additional Information (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) Contract	Mar. 31, 2015 USD ($) Contract	Dec. 31, 2015 Contract	Dec. 31, 2014 Contract
Derivative [Line Items]
Estimated amount related to derivatives reclassified to interest expense during the next 12 months	$ 109,000
Interest Rate Swaptions
Derivative [Line Items]
Number of derivative instruments outstanding | Contract	4		6
Proceeds from swaptions termination		$ 2,049,000
Eurodollar Future
Derivative [Line Items]
Number of derivative instruments outstanding | Contract	95,458	128,713	108,824	130,074
Derivative term of contract	3 months
Notional Amount	$ 1,000,000
Fair value of derivatives in net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to agreements	$ 11,440,000
Eurodollar Future | Minimum
Derivative [Line Items]
Futures contracts range	2016
Eurodollar Future | Maximum
Derivative [Line Items]
Futures contracts range	2021