Condensed Consolidated Statements of Shareholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Series A	Series B	Preferred Shares of Beneficial Interest Series A	Preferred Shares of Beneficial Interest Series A Series A	Common Shares of Beneficial Interest	Paid-in Capital	Paid-in Capital Series A	Accumulated Deficit and Distributions in Excess of Net Earnings	Accumulated Deficit and Distributions in Excess of Net Earnings Series A	Accumulated Deficit and Distributions in Excess of Net Earnings Series B	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2016				125		69,370,609
Beginning balance at Dec. 31, 2016	$ (149,455)			$ 0		$ 694	$ 392,591		$ (532,196)			$ (10,544)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	4,384								4,384
Other comprehensive loss	3,616											3,616
Distributions on preferred shares of beneficial interest – Series B	(7,108)								(7,108)
Distributions on common shares	(5,053)								(5,053)
Preferred Stock, Accretion of Redemption Discount	(220)						(220)
Stock-based compensation expense (Stock Options and Restricted Stock Units)	587						587
Ending balance at Mar. 31, 2017	(153,249)			$ 0		$ 694	392,958		(539,973)			(6,928)
Ending balance (in shares) at Mar. 31, 2017				125		69,370,609
Beginning balance (in shares) at Dec. 31, 2016				125		69,370,609
Beginning balance at Dec. 31, 2016	(149,455)			$ 0		$ 694	392,591		(532,196)			(10,544)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(8,608)
Ending balance at Sep. 30, 2017	$ (187,338)			$ 0		$ 694	393,694		(577,297)			(4,429)
Ending balance (in shares) at Sep. 30, 2017				125		69,370,609
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions declared per common share of beneficial interest (in dollars per share)	$ 0.22
Beginning balance (in shares) at Mar. 31, 2017				125		69,370,609
Beginning balance at Mar. 31, 2017	$ (153,249)			$ 0		$ 694	392,958		(539,973)			(6,928)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(8,385)								(8,385)
Other comprehensive loss	1,098											1,098
Redemption and distributions on preferred shares of beneficial interest – Series A	(8)								(8)
Redemption and distributions on preferred shares of beneficial interest – Series A (in shares)				0
Distributions on preferred shares of beneficial interest – Series B	(7,109)								(7,109)
Distributions on common shares	(5,053)								(5,053)
Preferred Stock, Accretion of Redemption Discount	(218)						(218)
Stock-based compensation expense (Stock Options and Restricted Stock Units)	586						586
Ending balance at Jun. 30, 2017	(172,338)			$ 0		$ 694	393,326		(560,528)			(5,830)
Ending balance (in shares) at Jun. 30, 2017				125		69,370,609
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(4,607)								(4,607)
Other comprehensive loss	1,401											1,401
Distributions on preferred shares of beneficial interest – Series B	(7,109)								(7,109)
Distributions on common shares	(5,053)								(5,053)
Preferred Stock, Accretion of Redemption Discount	(219)						(219)
Stock-based compensation expense (Stock Options and Restricted Stock Units)	587						587
Ending balance at Sep. 30, 2017	$ (187,338)			$ 0		$ 694	393,694		(577,297)			(4,429)
Ending balance (in shares) at Sep. 30, 2017				125		69,370,609
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions declared per common share of beneficial interest (in dollars per share)	$ 0.07
Beginning balance (in shares) at Dec. 31, 2017				125		69,370,609
Beginning balance at Dec. 31, 2017	$ (186,924)			$ 0		$ 694	394,082		(581,470)			(230)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(8,639)								(8,639)
Other comprehensive loss	(938)											(938)
Redemption and distributions on preferred shares of beneficial interest – Series A		$ (134)						$ (133)		$ (1)
Redemption and distributions on preferred shares of beneficial interest – Series A (in shares)					(125)
Distributions on preferred shares of beneficial interest – Series B			$ (1,817)								$ (1,817)
Distributions on common shares	(21,436)								(21,436)
Stock-based compensation expense (Stock Options and Restricted Stock Units)	1,839						1,839
Stock-based compensation expense (modification of Restricted Stock Units)	2,600						2,600
Common stock issuance related to share-based payment plans, net of shares withheld for employee taxes	(259)					$ 1	(260)
Common stock issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)						125,763
Warrants exercise	0					$ 64	(64)
Warrants exercise (in shares)						6,426,818
Issuance of common shares	484,905					$ 334	484,571
Issuance of common shares (in shares)						33,350,000
Conversion of mezzanine Series B Preferred shares	372,791					$ 332	372,459
Conversion of mezzanine Series B Preferred shares (in shares)						33,240,258
Ending balance at Mar. 31, 2018	641,988			$ 0		$ 1,425	1,255,094		(613,363)			(1,168)
Ending balance (in shares) at Mar. 31, 2018				0		142,513,448
Beginning balance (in shares) at Dec. 31, 2017				125		69,370,609
Beginning balance at Dec. 31, 2017	(186,924)			$ 0		$ 694	394,082		(581,470)			(230)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	45,306
Ending balance at Sep. 30, 2018	$ 731,003			$ 0		$ 1,479	1,349,761		(612,795)			(7,442)
Ending balance (in shares) at Sep. 30, 2018				0		147,861,840
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions declared per common share of beneficial interest (in dollars per share)	$ 0.54
Beginning balance (in shares) at Mar. 31, 2018				0		142,513,448
Beginning balance at Mar. 31, 2018	$ 641,988			$ 0		$ 1,425	1,255,094		(613,363)			(1,168)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	29,405								29,405
Other comprehensive loss	(4,021)											(4,021)
Distributions on common shares	(27,250)								(27,250)
Stock-based compensation expense (Stock Options and Restricted Stock Units)	2,256						2,256
Stock-based compensation expense (modification of Restricted Stock Units)	(559)						(559)
Common stock issuance related to share-based payment plans, net of shares withheld for employee taxes	998					$ 10	988
Common stock issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)						945,604
Ending balance at Jun. 30, 2018	642,817			$ 0		$ 1,435	1,257,779		(611,208)			(5,189)
Ending balance (in shares) at Jun. 30, 2018				0		143,459,052
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	24,540								24,540
Other comprehensive loss	(253)											(253)
Distributions on common shares	(28,072)								(28,072)
Stock-based compensation expense (Stock Options and Restricted Stock Units)	2,042						2,042
Common stock issuance related to share-based payment plans, net of shares withheld for employee taxes	(1,675)					$ 4	(1,679)
Common stock issuance related to share-based payment plans, net of shares withheld for employee taxes (in shares)						402,788
Other	(415)						(360)		1,945			(2,000)
Issuance of common shares	92,019					$ 40	91,979
Issuance of common shares (in shares)						4,000,000
Ending balance at Sep. 30, 2018	$ 731,003			$ 0		$ 1,479	$ 1,349,761		$ (612,795)			$ (7,442)
Ending balance (in shares) at Sep. 30, 2018				0		147,861,840
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions declared per common share of beneficial interest (in dollars per share)	$ 0.19