Quarterly Operating Results (Unaudited) - Quarterly Operating Results (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 36,750,863	$ 33,941,875	$ 36,865,108	$ 30,975,630	$ 29,825,377	$ 31,764,453	$ 36,339,701	$ 25,010,389	$ 138,533,476	$ 122,939,919	$ 89,374,527
Total operating expenses	34,127,473	31,976,036	29,689,455	27,410,462	30,441,730	28,622,841	29,120,620	22,249,394	123,203,426	110,434,588	78,967,048
Net operating income (loss)	2,623,390	1,965,839	7,175,653	3,565,168	(616,353)	3,141,612	7,219,081	2,760,995	15,330,050	12,505,331	10,407,479
Net income (loss)	(711,959)	4,636,644	1,759,109	713,859	(4,213,362)	(280,014)	2,752,555	1,002,314	6,397,653	(738,509)	(4,473,592)
Net income (loss) attributable to the Company	$ (522,174)	$ 3,872,394	$ 1,431,110	$ 575,336	$ (3,319,460)	$ (214,902)	$ 2,166,689	$ 783,002	$ 5,356,666	$ (584,671)	$ (3,483,969)
Earnings (loss) per share – basic and diluted	$ (0.04)	$ 0.27	$ 0.13	$ 0.05	$ (0.31)	$ (0.02)	$ 0.21	$ 0.08	$ 0.43	$ (0.06)	$ (0.34)