Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Consolidated Statements of Operations and Comprehensive (loss) Income [Abstract]
General and administrative expenses	$ (1,725)	$ (1,615)	$ (5,174)	$ (5,115)
Recovery of affiliate doubtful receivable	5,854		5,854
Operating income (loss)	4,129	(1,615)	680	(5,115)
Interest and investment income	16	1,406	1,045	4,574
Interest expense	(9)	(5)	(20)	(15)
Other expense	(2,300)	(1,048)	(6,440)	(3,019)
Income (loss) before income taxes and equity in net income (loss) of affiliates	1,836	(1,262)	(4,735)	(3,575)
Income tax (provision) benefit	(309)	(1,275)	(956)	(5,501)
Income (loss) before equity in net income (loss) of affiliates	1,527	(2,537)	(5,691)	(9,076)
Equity in net (loss) income of affiliates	49,645	8,784	9,086	92,066
Net (loss) income	51,172	6,247	3,395	82,990
Other comprehensive income (loss), net of tax	(7,220)	(16,261)	6,891	(29,313)
Comprehensive (loss) income	$ 43,952	$ (10,014)	$ 10,286	$ 53,677
Net (loss) income per share:
Basic	$ 1.65	$ 0.20	$ 0.11	$ 2.68
Diluted	$ 1.64	$ 0.20	$ 0.11	$ 2.66
Weighted average common shares outstanding:
Basic	30,933	30,933	30,933	30,933
Diluted	31,026	31,008	31,017	31,008