Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) [Abstract]
General and administrative expenses	$ (2,080)	$ (1,336)	$ (3,697)	$ (2,676)
Operating income (loss)	(2,080)	(1,336)	(3,697)	(2,676)
Interest and investment income	14	110	104	401
Interest expense	(5)	(4)	(8)	(7)
Other income (expense)	(2,710)	(651)	(3,084)	(1,576)
Income (loss) from continuing operations before income taxes and equity in net income (loss) of affiliates	(4,781)	(1,881)	(6,685)	(3,858)
Income tax (provision) benefit	(2,279)	(9,480)	(6,033)	(20,152)
Income (loss) from continuing operations before equity in net income (loss) of affiliates	(7,060)	(11,361)	(12,718)	(24,010)
Equity in net income (loss) of affiliates	25,087	64,363	(51,758)	62,194
Income (loss) from continuing operations	18,027	53,002	(64,476)	38,184
Income (loss) from discontinued operations, net of tax provision	(227)	(1)	(366)	(8)
Net income (loss)	17,800	53,001	(64,842)	38,176
Other comprehensive income (loss), net of tax	1,128	286	1,362	1,049
Comprehensive income (loss)	$ 18,928	$ 53,287	$ (63,480)	$ 39,225
Earnings Per Share, Basic [Abstract]
Income (loss) from continuing operations	$ 0.58	$ 1.71	$ (2.09)	$ 1.23
Income (loss) from discontinued operations, net of tax	(0.01)		(0.01)
Net income (loss)	0.57	1.71	(2.10)	1.23
Earnings Per Share Diluted [Abstract]
Income (loss) from continuing operations	0.56	1.67	(2.09)	1.19
Income (loss) from discontinued operations, net of tax	(0.01)		(0.01)
Net income (loss)	$ 0.55	$ 1.67	$ (2.10)	$ 1.19
Weighted average common shares outstanding:
Basic	30,927	30,920	30,923	30,920
Diluted	31,006	31,004	30,923	31,004