CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Series A Preferred Stock [Member] Total Stockholders' Equity [Member]	Series A Preferred Stock [Member] Accumulated Deficit [Member]	Series A Preferred Stock [Member] Non-Controlling Interests [Member]	Series A Preferred Stock [Member]	Series B Preferred Stock [Member] Total Stockholders' Equity [Member]	Series B Preferred Stock [Member] Accumulated Deficit [Member]	Series B Preferred Stock [Member] Non-Controlling Interests [Member]	Series B Preferred Stock [Member]	Total Stockholders' Equity [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Non-Controlling Interests [Member]	Total
Balance at Dec. 31, 2016				$ 9,448					$ 168,362	$ 90	$ 162,664	$ (3,840)		$ 168,362
Balance (in shares) at Dec. 31, 2016				10,000						8,956,354
Equity offering costs related to issuance of preferred stock				$ (3)					(3)					(3)
Stock dividend paid on preferred stock									1,194	$ 1	1,193			1,194
Stock dividend paid on preferred stock (in Shares)										57,850
Proceeds from issuance of common stock, net of offering costs									83,935	$ 40	83,895			83,935
Proceeds from issuance of common stock, net of offering costs (in shares)										4,025,000
At-the-market issuance of common stock, net of offering costs									24,194	$ 10	24,184			24,194
At-the-market issuance of common stock, net of offering costs (in shares)										1,093,202
Repurchase and retirement of shares related to vested restricted stock									(128)		(128)			(128)
Repurchase and retirement of shares related to vested restricted stock (in shares)										(5,470)
Issuances of stock-based awards									(9)	$ 1	(10)			(9)
Issuances of stock-based awards (in shares)										111,414
Stock-based compensation									727		727			727
Dividends declared on preferred stock									(723)			(723)		(723)
Dividends declared on common stock									(8,132)			(8,132)		(8,132)
Net income									6,977			6,977		6,977
Balance at Jun. 30, 2017				$ 9,445					276,394	$ 142	272,525	(5,718)		276,394
Balance (in shares) at Jun. 30, 2017				10,000						14,238,350
Balance at Dec. 31, 2017				$ 37,764					305,820	$ 144	276,814	(8,902)		305,820
Balance (in shares) at Dec. 31, 2017				40,000						14,429,055
Stock dividend paid on preferred stock									2,169	$ 1	2,168			2,169
Stock dividend paid on preferred stock (in Shares)										122,250
Issuance of preferred stock, net of offering costs				$ 69,404				$ 35,980	105,384					105,384
Issuance of preferred stock, net of offering costs (in shares)				70,000				1,500,000
At-the-market issuance of preferred stock, net of offering costs								$ 1,483	1,483					1,483
At-the-market issuance of preferred stock, net of offering costs (in shares)								71,734
Proceeds from issuance of common stock, net of offering costs									81,149	$ 46	81,103			81,149
Proceeds from issuance of common stock, net of offering costs (in shares)										4,600,000
At-the-market issuance of common stock, net of offering costs									682		682			682
At-the-market issuance of common stock, net of offering costs (in shares)										44,016
Repurchase and retirement of shares related to vested restricted stock									(314)		(314)			(314)
Repurchase and retirement of shares related to vested restricted stock (in shares)										(16,513)
Issuances of stock-based awards										$ 1	(1)
Issuances of stock-based awards (in shares)										75,333
Stock-based compensation									1,184		1,184			1,184
Dividends declared on preferred stock	$ (6,926)	$ (6,926)		$ (6,926)	$ (1,249)	$ (1,249)		$ (1,249)
Dividends declared on common stock									(11,795)			(11,795)		(11,795)
Net income									16,151			16,151		16,151
Balance at Jun. 30, 2018				$ 107,168				$ 37,463	$ 493,738	$ 192	$ 361,636	$ (12,721)		$ 493,738
Balance (in shares) at Jun. 30, 2018				110,000				1,571,734		19,254,141