Offering Costs and Formation Transaction Expenses - Additional Information (Detail) (USD $)	6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Incurred external offering cost	$ 1,939,357
External offering costs during period	187,013	389,229
Offering costs Due to Supervisor	154,433		422,031
Additional offering costs for work done by Supervisor's employees	73,602	37,602
Accumulated correction impacted amount	$ 1,939,357	$ 252,337	$ 1,752,344