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)	28,364			28,470			28,470	(106)
Net unrealized gain (loss) on securities available-for-sale	(389)				(389)		(389)
Foreign currency translation adjustments	(271)				(271)		(271)
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)
Ending Balance (in shares) at Sep. 30, 2015		8,667,666				943,909
Beginning Balance at Dec. 31, 2014	23,071
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	(3,330)
Activity of noncontrolling interests, net	30,154
Ending Balance at Sep. 30, 2015	49,895
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)	36,076			36,076			36,076	0
Net unrealized gain (loss) on securities available-for-sale	230				230		230
Foreign currency translation adjustments	569				569		569
Cash dividends declared	(11,003)		(11,003)				(11,003)
Repurchases of common shares	$ (72,216)	$ (6)	(47,207)			$ (25,003)	(72,216)
Repurchases of common shares (in shares)	844,671	844,671				288,155
Issuance of common shares related to employee stock transactions	$ 992	$ 1	991				992
Issuance of common shares related to employee stock transactions (in shares)		55,480
Taxes paid on stock-based compensation	(1,518)		(1,518)				(1,518)
Stock-based compensation	8,815		8,815				8,815
Tax deficiencies from stock-based compensation	(1,603)		(1,603)				(1,603)
Ending Balance at Sep. 30, 2016	469,799	$ 91	$ 1,089,350	(436,705)	$ (235)	$ (182,702)	469,799	0
Ending Balance (in shares) at Sep. 30, 2016		7,609,753				1,502,299
Beginning Balance at Dec. 31, 2015	73,864
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	770
Activity of noncontrolling interests, net	(44,333)			$ (167)			$ (167)	$ 167
Ending Balance at Sep. 30, 2016	$ 30,301