Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total Attributed To Shareholders [Member]	Non-controlling Interests [Member]
Beginning Balance at Dec. 31, 2014	$ 563,352	$ 96	$ 1,148,908	$ (507,521)	$ (242)	$ (77,699)	$ 563,542	$ (190)
Beginning Balance (in shares) at Dec. 31, 2014		8,975,833				575,441
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	28,919			29,119			29,119	(200)
Net unrealized gain (loss) on securities available-for-sale	(99)				(99)		(99)
Foreign currency translation adjustments	(320)				(320)		(320)
Cash dividends declared	(8,143)		(8,143)				(8,143)
Repurchases of common shares	$ (28,000)					$ (28,000)	(28,000)
Repurchases of common shares (in shares)	212,588	212,588				212,588
Issuance of common shares related to employee stock transactions	$ 787		787				787
Issuance of common shares related to employee stock transactions (in shares)		55,384
Taxes paid on stock-based compensation	(4,841)		(4,841)				(4,841)
Stock-based compensation	6,168		6,168				6,168
Excess tax benefits from stock-based compensation	1,150		1,150				1,150
Ending Balance at Jun. 30, 2015	558,973	$ 96	1,144,029	(478,402)	(661)	$ (105,699)	559,363	(390)
Ending Balance (in shares) at Jun. 30, 2015		8,818,629				788,029
Beginning Balance at Dec. 31, 2014	23,071
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	(182)
Activity of noncontrolling interests, net	32,688
Ending Balance at Jun. 30, 2015	55,577
Beginning Balance at Dec. 31, 2015	509,457	$ 96	1,140,875	(472,614)	(1,034)	$ (157,699)	509,624	(167)
Beginning Balance (in shares) at Dec. 31, 2015		8,398,944				1,214,144
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	20,451			20,451			20,451	0
Net unrealized gain (loss) on securities available-for-sale	281				281		281
Foreign currency translation adjustments	569				569		569
Cash dividends declared	(7,452)		(7,452)				(7,452)
Repurchases of common shares	$ (62,139)	$ (6)	(47,133)			$ (15,000)	(62,139)
Repurchases of common shares (in shares)	732,713	732,713				176,204
Issuance of common shares related to employee stock transactions	$ 964	$ 1	963				964
Issuance of common shares related to employee stock transactions (in shares)		51,832
Taxes paid on stock-based compensation	(1,332)		(1,332)				(1,332)
Stock-based compensation	6,620		6,620				6,620
Tax deficiencies from stock-based compensation	(1,313)		(1,313)				(1,313)
Ending Balance at Jun. 30, 2016	466,106	$ 91	$ 1,091,228	$ (452,163)	$ (184)	$ (172,699)	$ 466,273	$ (167)
Ending Balance (in shares) at Jun. 30, 2016		7,718,063				1,390,348
Beginning Balance at Dec. 31, 2015	73,864
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	119
Activity of noncontrolling interests, net	(46,838)
Ending Balance at Jun. 30, 2016	$ 27,145