CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Preference shares	Common shares	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit	Treasury shares	Noncontrolling interests in subsidiaries
Beginning balance at Dec. 31, 2018		$ 465,000	$ 879	$ 749,418	$ (65,616)	$ (563,891)	$ (31,515)	$ 641
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options and issuance of shares			2	(2)
Share-based compensation expense				1,254
Change in net unrealized (losses) gains on investment					61,476
Foreign currency translation adjustment					3,920			78
Net income (loss)	$ (36,636)					(36,636)
Disposal of subsidiaries								(719)
Ending balance at Mar. 31, 2019	584,289	465,000	881	750,670	(220)	(600,527)	(31,515)	0
Beginning balance at Dec. 31, 2019		465,000	882	751,327	17,836	(695,794)	(31,533)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options and issuance of shares			8	(8)
Share-based compensation expense				543
Change in net unrealized (losses) gains on investment					(44,121)
Foreign currency translation adjustment					(3)
Net income (loss)	20,861					20,861
Disposal of subsidiaries								0
Ending balance at Mar. 31, 2020	$ 484,998	$ 465,000	$ 890	$ 751,862	$ (26,288)	$ (674,933)	$ (31,533)	$ 0