Transactions with Related Parties - Additional Information (Details) (USD $)	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 31, 2014 Person	Dec. 31, 2013
Related Party Transaction [Line Items]
Number of independent directors		5
Management agreement initial expiration date		Feb. 23, 2016
Management agreement additional term of expiration		1 year
Prior notice for uncertain termination (in days)		180 days
Proportion of average annual management fee		400.00%
Period of annual management fees earned (in years)		2 years
Management fee payable		$ 3,198,000	$ 2,752,000
Financial interest at an annual rate	300,000
Company's Equity Up To $250 Million
Related Party Transaction [Line Items]
Management fee payable		250,000,000
Management fee bases per annum		1.50%
Company's Equity In Excess Of $250 Million And Up To $500 Million
Related Party Transaction [Line Items]
Management fee payable		500,000,000
Management fee bases per annum		1.10%
Management fee payable, minimum		250,000,000
Company's Equity In Excess Of $500 Million And Up To $750 Million
Related Party Transaction [Line Items]
Management fee payable		750,000,000
Management fee bases per annum		0.80%
Management fee payable, minimum		500,000,000
Company's Equity In Excess Of $750 Million
Related Party Transaction [Line Items]
Management fee payable		$ 750,000,000
Management fee bases per annum		0.50%