CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Treasury stock, at cost	Non-controlling interests
Balance (in shares) at Dec. 31, 2019		25,413
Balance at Dec. 31, 2019	$ (21,357)	$ 25,413	$ 133,669	$ 272,026	$ (453,934)	$ 1,469
Increase (Decrease) in Equity
Net loss	(11,545)			(11,650)		105
Distributions to non-controlling interest holders	(311)					(311)
Share-based compensation expense	2,894		2,894
Issuance of restricted share units and restricted shares	0			(4,796)	4,796
Treasury shares withheld for the payment of tax on restricted share unit and restricted share issuances	(1,205)			(3,114)	1,909
Balance (in shares) at Mar. 31, 2020		25,413
Balance at Mar. 31, 2020	(31,524)	$ 25,413	136,563	252,466	(447,229)	1,263
Balance (in shares) at Dec. 31, 2019		25,413
Balance at Dec. 31, 2019	(21,357)	$ 25,413	133,669	272,026	(453,934)	1,469
Increase (Decrease) in Equity
Net loss	(59,306)
Balance (in shares) at Sep. 30, 2020		25,413
Balance at Sep. 30, 2020	(76,578)	$ 25,413	140,225	198,756	(442,107)	1,135
Balance (in shares) at Mar. 31, 2020		25,413
Balance at Mar. 31, 2020	(31,524)	$ 25,413	136,563	252,466	(447,229)	1,263
Increase (Decrease) in Equity
Net loss	(34,864)			(35,061)		197
Distributions to non-controlling interest holders	(180)					(180)
Share-based compensation expense	1,930		1,930
Issuance of restricted share units and restricted shares	0			(3,177)	3,177
Treasury shares withheld for the payment of tax on restricted share unit and restricted share issuances	(212)			(1,205)	993
Balance (in shares) at Jun. 30, 2020		25,413
Balance at Jun. 30, 2020	(64,850)	$ 25,413	138,493	213,023	(443,059)	1,280
Increase (Decrease) in Equity
Net loss	(12,897)			(13,237)		340
Distributions to non-controlling interest holders	(485)					(485)
Share-based compensation expense	1,732		1,732
Issuance of restricted share units and restricted shares	0			(747)	747
Treasury shares withheld for the payment of tax on restricted share unit and restricted share issuances	(78)			(283)	205
Balance (in shares) at Sep. 30, 2020		25,413
Balance at Sep. 30, 2020	(76,578)	$ 25,413	140,225	198,756	(442,107)	1,135
Balance (in shares) at Dec. 31, 2020		25,413
Balance at Dec. 31, 2020	(82,556)	$ 25,413	141,473	190,383	(441,034)	1,209
Increase (Decrease) in Equity
Net loss	(21,915)			(22,002)		87
Distributions to non-controlling interest holders	(1,395)					(1,395)
Share-based compensation expense	1,438		1,438
Issuance of restricted share units and restricted shares	0			(5,905)	5,905
Treasury shares withheld for the payment of tax on restricted share unit and restricted share issuances	(830)			(3,586)	2,756
Balance (in shares) at Mar. 31, 2021		25,413
Balance at Mar. 31, 2021	(105,258)	$ 25,413	142,911	158,890	(432,373)	(99)
Balance (in shares) at Dec. 31, 2020		25,413
Balance at Dec. 31, 2020	(82,556)	$ 25,413	141,473	190,383	(441,034)	1,209
Increase (Decrease) in Equity
Net loss	(58,897)			(58,746)
Balance (in shares) at Sep. 30, 2021		25,413
Balance at Sep. 30, 2021	(141,683)	$ 25,413	143,983	116,881	(427,214)	(746)
Balance (in shares) at Mar. 31, 2021		25,413
Balance at Mar. 31, 2021	(105,258)	$ 25,413	142,911	158,890	(432,373)	(99)
Increase (Decrease) in Equity
Net loss	(18,654)			(18,475)		(179)
Distributions to non-controlling interest holders	(356)					(356)
Share-based compensation expense	641		641
Issuance of restricted share units and restricted shares	0			(4,574)	4,574
Treasury shares withheld for the payment of tax on restricted share unit and restricted share issuances	(97)			(571)	474
Balance (in shares) at Jun. 30, 2021		25,413
Balance at Jun. 30, 2021	(123,724)	$ 25,413	143,552	135,270	(427,325)	(634)
Increase (Decrease) in Equity
Net loss	(18,328)			(18,269)		(59)
Distributions to non-controlling interest holders	(53)					(53)
Share-based compensation expense	431		431
Issuance of restricted share units and restricted shares	0			(84)	84
Treasury shares withheld for the payment of tax on restricted share unit and restricted share issuances	(9)			(36)	27
Balance (in shares) at Sep. 30, 2021		25,413
Balance at Sep. 30, 2021	$ (141,683)	$ 25,413	$ 143,983	$ 116,881	$ (427,214)	$ (746)