Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Consolidated Statements of Operations [Abstract]
General and administrative expenses	$ (1,615)	$ (1,715)	$ (5,115)	$ (5,109)
Operating income (loss)	(1,615)	(1,715)	(5,115)	(5,109)
Interest and investment income	1,406	1,263	4,574	3,340
Interest expense	(5)	(6)	(15)	(17)
Other expense	(1,048)	(1,749)	(3,019)	(2,937)
Income (loss) from continuing operations before income taxes and equity in net income (loss) of affiliates	(1,262)	(2,207)	(3,575)	(4,723)
Income tax (provision) benefit	(1,275)	(6,669)	(5,501)	(1,014)
Income (loss) from continuing operations before equity in net income (loss) of affiliates	(2,537)	(8,876)	(9,076)	(5,737)
Equity in net income (loss) of affiliates	8,784	55,095	92,066	56,734
Income (loss) from continuing operations	6,247	46,219	82,990	50,997
Income (loss) from discontinued operations, net of tax		(25)		(62)
Net income (loss)	6,247	46,194	82,990	50,935
Other comprehensive (loss) income, net of tax	(16,261)	(5,410)	(29,313)	2,362
Comprehensive income (loss)	$ (10,014)	$ 40,784	$ 53,677	$ 53,297
Basic
Income (loss) from continuing operations	$ 0.20	$ 1.49	$ 2.68	$ 1.65
Income (loss) from discontinued operations, net of tax
Net income (loss) per share	0.20	1.49	2.68	1.65
Diluted
Income (loss) from continuing operations	0.20	1.48	2.66	1.63
Income (loss) from discontinued operations, net of tax
Net income (loss) per share	$ 0.20	$ 1.48	$ 2.66	$ 1.63
Weighted average common shares outstanding:
Basic	30,933	30,933	30,933	30,933
Diluted	31,008	31,008	31,008	31,008