Derivative Financial Instruments - Summary of Outstanding Swaptions (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Derivatives, Fair Value [Line Items]
Assets, at Fair Value	$ 8,728,000	$ 6,391,000
Interest Rate Swaption [Member]
Derivatives, Fair Value [Line Items]
Assets, at Fair Value	65,000	1,217,000
Interest Rate Swaption [Member] | Less Than Or Equal To One Year [Member]
Derivatives, Fair Value [Line Items]
Swaption Cost	3,200,000	5,350,000
Assets, at Fair Value	$ 65,000	$ 1,217,000
Derivative Instruments Average Months To Expiration	2	6
Notional Amount	$ 175,000,000	$ 375,000,000
Derivative Average Fixed Interest Rate	3.29%	2.79%
Derivative Avergage Receive Rate	3 Month	3 Month
Term (Years)	10 years	7 years 4 months 29 days