Derivative Financial Instruments - Summary of Outstanding Swaptions (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Assets, at Fair Value	$ 6,391,000	$ 2,446,000
Interest Rate Swaption [Member]
Derivatives, Fair Value [Line Items]
Swaption Cost	5,350,000
Assets, at Fair Value	1,217,000	0
Derivative Instruments Average Months To Expiration	6
Notional Amount	375,000,000
Derivative Average Fixed Interest Rate	2.79%
Derivative Avergage Receive Rate	3 Month
Term (Years)	7 years 4 months 30 days
Interest Rate Swaption [Member] | Less Than Or Equal To One Year [Member]
Derivatives, Fair Value [Line Items]
Swaption Cost	5,350,000
Assets, at Fair Value	1,217,000
Derivative Instruments Average Months To Expiration	6
Notional Amount	$ 375,000,000
Derivative Average Fixed Interest Rate	2.79%
Derivative Avergage Receive Rate	3 Month
Term (Years)	7 years 4 months 30 days