Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Consolidated Statements of Operations and Comprehensive (loss) Income [Abstract]
General and administrative expenses	$ (1,648)	$ (1,803)
Operating income (loss)	(1,648)	(1,803)
Interest and investment income	937	1,602
Interest expense	(5)	(5)
Other expense	(1,437)	(1,216)
Income (loss) before income taxes and equity in net income (loss) of affiliates	(2,153)	(1,422)
Income tax (provision) benefit	(2,116)	(2,066)
Income (loss) before equity in net income (loss) of affiliates	(4,269)	(3,488)
Equity in net (loss) income of affiliates	(117,074)	42,004
Net (loss) income	(121,343)	38,516
Other comprehensive income (loss), net of tax	31,290	(6,406)
Comprehensive (loss) income	$ (90,053)	$ 32,110
Net (loss) income per share:
Basic	$ (3.92)	$ 1.25
Diluted	$ (3.92)	$ 1.23
Weighted average common shares outstanding:
Basic	30,933	30,933
Diluted	30,933	31,008