Consolidated Statements of Stockholders' Equity (USD $)	Total USD ($)	Preferred Stock USD ($)	Additional Paid-in Capital USD ($)	Accumulated Deficit and Distributions USD ($)	Accumulated Other Comprehensive Income (Loss) USD ($)	Common Class A	Common Class A Common Stock USD ($)	Common Class B Common Stock USD ($)
Stockholders' equity, beginning of year at Dec. 31, 2011	$ 189,808,272	$ 48,685,499	$ 271,617,462	$ (130,620,551)	$ 0		$ 31,466	$ 94,396
Stockholders' equity, beginning of year (in shares) at Dec. 31, 2011		37,748					3,146,527	9,439,583
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock (in shares)							41,445	124,331
Issuance of common stock	4,134,741		4,133,145	(61)			414	1,243
Redemption of common stocks (in shares)							(7,909)	(23,726)
Redemption of common stock	(743,115)		(742,799)				(79)	(237)
Dividends on preferred stock	0	373,992	(373,992)
Redemptions of preferred stock (in shares)		(356)
Redemptions of preferred stock	(459,436)	(459,436)
Commissions and discounts on stock sales and related dealer-manager fees	(361,364)		(361,364)
Other offering costs	(48,752)		(48,752)
Write-off of due to affiliates	27,315,249		27,315,249
Net income (loss)	(8,870,732)			(8,870,732)
Other comprehensive income (loss)	(687,674)				(687,674)
Stockholders' equity, end of year at Dec. 31, 2012	210,087,189	48,600,055	301,538,949	(139,491,344)	(687,674)		31,801	95,402
Stockholders' equity, end of year (in shares) at Dec. 31, 2012		37,392					3,180,063	9,540,188
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock (in shares)							10,526,316	0
Issuance of common stock	142,105,266		142,000,003				105,263	0
Restricted stock grants, net of amounts withheld for income taxes (in shares)							191,561	900
Long term incentive plan, net of amounts withheld for income taxes	1,211,982		1,210,057				1,916	9
Forfeiture of restricted stock award (in shares)							(202)	(606)
Forfeiture of restricted stock award	0		(197)	205			(2)	(6)
Fractional share conversion (in shares)							17,662	(17,662)
Conversion to Class A Shares							176	(176)
Redemption of common stocks (in shares)							(15,018)	(29,371)
Redemption of common stock	(680,495)		(680,050)				(150)	(295)
Dividends on preferred stock	0	359,784	(359,784)
Redemptions of preferred stock (in shares)		(37,392)
Redemptions of preferred stock	(48,959,839)	(48,959,839)
Other offering costs	(11,591,773)		(11,591,773)
Net income (loss)	(13,196,920)			(13,196,920)
Other comprehensive income (loss)	956,042				956,042
Stockholders' equity, end of year at Dec. 31, 2013	279,931,452	0	432,117,205	(152,688,059)	268,368		139,004	94,934
Stockholders' equity, end of year (in shares) at Dec. 31, 2013		0					13,900,382	9,493,449
Dividends on common stock (in USD per share)	0.47
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock (in shares)							15,953,947
Issuance of common stock	190,222,034		190,062,495				159,539
Restricted stock grants, net of amounts withheld for income taxes (in shares)							9,694
Long term incentive plan, net of amounts withheld for income taxes	381,249		381,152				97
Fractional share conversion (in shares)							6,328,952	(6,328,952)
Conversion to Class A Shares							63,290	(63,290)
Redemption of common stocks (in shares)							(7)	(21)
Redemption of common stock	(370)		(370)				0	0
Dividends on common stock	(15,335,478)			(15,335,478)
Other offering costs	(10,041,959)		(10,041,959)
Net income (loss)	659,549			659,549
Other comprehensive income (loss)	(1,124,130)				(1,124,130)
Stockholders' equity, end of year at Dec. 31, 2014	$ 444,692,347	$ 0	$ 612,518,523	$ (167,363,988)	$ (855,762)		$ 361,930	$ 31,644
Stockholders' equity, end of year (in shares) at Dec. 31, 2014		0					36,192,968	3,164,476