Issuances of Additional Beneficial Certificate Units (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Issuances Of Additional Beneficial Unit Certificates [Abstract]
Common Stock, Shares Authorized			225,000,000
Common Stock shares, issued	9,200,000		8,280,000
Sale Price of Common Stock per Share	$ 5.95		$ 6.25
Proceeds from Issuance of Common Stock	$ 51,300,000	$ 51,288,699	$ 48,213,603
Payments of Stock Issuance Costs	$ 3,500,000	$ 3,451,301	$ 3,536,397