Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) [Abstract]
General and administrative expenses	$ (1,709)	$ (1,652)	$ (4,900)	$ (5,349)
Operating income (loss)	(1,709)	(1,652)	(4,900)	(5,349)
Interest and investment income	44	15	140	119
Interest expense	(6)	(5)	(15)	(13)
Other income (expense)	(187)	(164)	(1,306)	(3,248)
Income (loss) from continuing operations before income taxes and equity in net income (loss) of affiliates	(1,858)	(1,806)	(6,081)	(8,491)
Income tax (provision) benefit	(8,911)	36,934	(31,066)	30,901
Income (loss) from continuing operations before equity in net income (loss) of affiliates	(10,769)	35,128	(37,147)	22,410
Equity in net income (loss) of affiliates	6,948	(38,475)	96,799	(90,233)
(Loss) income from continuing operations	(3,821)	(3,347)	59,652	(67,823)
Income (loss) from discontinued operations, net of tax provision	(71)	(208)	(306)	(574)
Net (loss) income	(3,892)	(3,555)	59,346	(68,397)
Other comprehensive income (loss), net of tax	1,713	(698)	11,289	664
Comprehensive income (loss)	$ (2,179)	$ (4,253)	$ 70,635	$ (67,733)
Net income (loss) per share: Basic
(Loss) income from continuing operations	$ (0.12)	$ (0.11)	$ 1.93	$ (2.19)
Income (loss) from discontinued operations, net of tax		(0.01)	(0.01)	(0.02)
Net (loss) income	(0.12)	(0.12)	1.92	(2.21)
Net income (loss) per share: Diluted
(Loss) income from continuing operations	(0.12)	(0.11)	1.85	(2.19)
Income (loss) from discontinued operations, net of tax		(0.01)	(0.01)	(0.02)
Net (loss) income	$ (0.12)	$ (0.12)	$ 1.84	$ (2.21)
Weighted average common shares outstanding:
Basic	30,933	30,933	30,933	30,926
Diluted	30,933	30,933	31,008	30,926