CONDENSED CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ in Thousands	Total	Class A Common Shares [Member]	Class B Common Shares [Member]	Class C Common Shares [Member]	Series A Preferred Shares [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Non-Controlling Interest [Member]
Beginning balance at Dec. 31, 2017	$ 1,320,860	$ 324	$ 13	$ 31	$ 28	$ 1,116,060	$ (229,760)	$ 434,164
Beginning balance, shares at Dec. 31, 2017		32,416,000	1,329,000	3,151,000	2,800,000
Net income (loss)	5,599						3,557	2,042
Common dividends and distributions declared	(28,078)						(17,994)	(10,084)
Preferred dividends declared	(2,453)						(2,453)
Vesting of restricted share units, shares		14,000
Share-based compensation	3,379					3,379
Share class surrenders, shares			(7,000)
Preferred stock offering costs	(113)					(113)
Stock issued in conversion of securities		$ 31
Stock issued in conversion securities, shares		3,150,281
Stock sold in conversion of securities, shares				(3,150,000)
Stock sold in conversion of securities				$ (31)
OP Unit exchanges		$ 1				2,925		(2,926)
OP Unit exchanges, shares		98,923
Ending balance at Jun. 30, 2018	1,299,194	$ 356	$ 13		$ 28	1,122,251	(246,650)	423,196
Ending balance, shares at Jun. 30, 2018		35,679,000	1,322,000	1,000	2,800,000
Beginning balance at Mar. 31, 2018	1,322,569	$ 352	$ 13	$ 4	$ 28	1,116,841	(229,652)	434,983
Beginning balance, shares at Mar. 31, 2018		35,209,000	1,329,000	372,000	2,800,000
Net income (loss)	(10,602)						(6,771)	(3,831)
Common dividends and distributions declared	(14,032)						(9,002)	(5,030)
Preferred dividends declared	(1,225)						(1,225)
Share-based compensation	2,510					2,510
Share class surrenders, shares			(7,000)
Preferred stock offering costs	(25)					(25)
Stock issued in conversion of securities	(1)	$ 3
Stock issued in conversion securities, shares		371,160
Stock sold in conversion of securities, shares				(371,000)
Stock sold in conversion of securities				$ (4)
OP Unit exchanges		$ 1				2,925		(2,926)
OP Unit exchanges, shares		98,923
Ending balance at Jun. 30, 2018	1,299,194	$ 356	$ 13		$ 28	1,122,251	(246,650)	423,196
Ending balance, shares at Jun. 30, 2018		35,679,000	1,322,000	1,000	2,800,000
Beginning balance at Dec. 31, 2018	1,150,458	$ 357	$ 13		$ 28	1,124,504	(344,132)	369,688
Beginning balance, shares at Dec. 31, 2018		35,667,521	1,322,365		2,800,000
Net income (loss)	(36,779)						(23,870)	(12,909)
Cumulative effect of accounting change (see Note 2)	(1,286)						(1,286)
Common dividends and distributions declared	(14,026)						(8,996)	(5,030)
Preferred dividends declared	(2,450)						(2,450)
Vesting of restricted share units, shares		(57,000)
Vesting of restricted share units	(3,413)	$ (1)				(3,412)
Share-based compensation	3,016	$ 1				3,015
Share-based compensation, shares		72,000
Share class surrenders			$ (1)			1
Share class surrenders, shares			(75,000)
OP Unit exchanges		$ 11				20,350		(20,361)
OP Unit exchanges, shares		1,145,735
Ending balance at Jun. 30, 2019	1,095,520	$ 368	$ 12		$ 28	1,144,458	(380,734)	331,388
Ending balance, shares at Jun. 30, 2019		36,828,991	1,247,060		2,800,000
Beginning balance at Mar. 31, 2019	1,122,980	$ 357	$ 13		$ 28	1,124,457	(362,606)	360,731
Beginning balance, shares at Mar. 31, 2019		35,690,000	1,322,000		2,800,000
Net income (loss)	(25,885)						(16,903)	(8,982)
Preferred dividends declared	(1,225)						(1,225)
Vesting of restricted share units, shares		(34,000)
Vesting of restricted share units	(1,800)	$ (1)				(1,799)
Share-based compensation	1,450	$ 1				1,449
Share-based compensation, shares		27,000
Share class surrenders			$ (1)			1
Share class surrenders, shares			(75,000)
OP Unit exchanges		$ 11				20,350		(20,361)
OP Unit exchanges, shares		1,145,735
Ending balance at Jun. 30, 2019	$ 1,095,520	$ 368	$ 12		$ 28	$ 1,144,458	$ (380,734)	$ 331,388
Ending balance, shares at Jun. 30, 2019		36,828,991	1,247,060		2,800,000