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]	Redeemable Non-controlling Interests [Member]
Beginning Balance at Dec. 31, 2013	$ 492,868	$ 95	$ 1,135,644	$ (605,221)	$ (150)	$ (37,438)	$ 492,930	$ (62)	$ 42,186
Beginning Balance (in shares) at Dec. 31, 2013		9,105,521				350,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	78,737			78,821			78,821	(84)	(183)
Net unrealized gain (loss) on securities available-for-sale	90				90		90
Foreign currency translation adjustments	(80)				(80)		(80)
Activity of noncontrolling interests, net									(19,738)
Cash dividends declared	(8,333)		(8,333)				(8,333)
Repurchases of common shares	$ (26,257)					$ (26,257)	(26,257)
Repurchases of common shares (in shares)	136,874	136,874				136,874
Issuance of common shares related to employee stock transactions	$ 1,224		1,224				1,224
Issuance of common shares related to employee stock transactions (in shares)		90,731
Taxes paid on stock-based compensation	(9,512)		(9,512)				(9,512)
Stock-based compensation	6,604		6,604				6,604
Excess tax benefits from stock-based compensation	25,089		25,089				25,089
Ending Balance at Sep. 30, 2014	560,430	$ 95	1,150,716	(526,400)	(140)	$ (63,695)	560,576	(146)	22,265
Ending Balance (in shares) at Sep. 30, 2014		9,059,378				486,874
Beginning Balance at Dec. 31, 2014	563,352	$ 96	1,148,908	(507,521)	(242)	$ (77,699)	563,542	(190)	23,071
Beginning Balance (in shares) at Dec. 31, 2014		8,975,833				575,441
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	28,364			28,470			28,470	(106)	(3,330)
Net unrealized gain (loss) on securities available-for-sale	(389)				(389)		(389)
Foreign currency translation adjustments	(271)				(271)		(271)
Activity of noncontrolling interests, net									30,154
Cash dividends declared	(12,136)		(12,136)				(12,136)
Repurchases of common shares	$ (45,000)					$ (45,000)	(45,000)
Repurchases of common shares (in shares)	368,468	368,468				368,468
Issuance of common shares related to employee stock transactions	$ 796		796				796
Issuance of common shares related to employee stock transactions (in shares)		60,301
Taxes paid on stock-based compensation	(5,080)		(5,080)				(5,080)
Stock-based compensation	8,656		8,656				8,656
Excess tax benefits from stock-based compensation	1,038		1,038				1,038
Ending Balance at Sep. 30, 2015	$ 539,330	$ 96	$ 1,142,182	$ (479,051)	$ (902)	$ (122,699)	$ 539,626	$ (296)	$ 49,895
Ending Balance (in shares) at Sep. 30, 2015		8,667,666				943,909