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
Balance, Shares at Dec. 31, 2013		9,105,521				350,000
Net income (loss)	41,441			41,481			41,481	(40)	118
Net unrealized gain (loss) on securities available-for-sale	185				185		185
Foreign currency translation adjustments	13				13		13
Activity of noncontrolling interests, net									(31,907)
Cash dividends declared	(4,179)		(4,179)				(4,179)
Repurchases of common shares	$ (12,500)					$ (12,500)	(12,500)
Repurchases of common shares, Shares	66,913	(66,913)				66,913
Issuance of common shares related to employee stock transactions	$ 954		954				954
Issuance of common shares related to employee stock transactions, shares		80,392
Taxes paid on stock-based compensation	(9,271)		(9,271)				(9,271)
Stock-based compensation	4,333		4,333				4,333
Excess tax benefits from stock-based compensation	583		583				583
Ending Balance at Jun. 30, 2014	514,427	$ 95	1,128,064	(563,740)	48	$ (49,938)	514,529	(102)	10,397
Balance, Shares at Jun. 30, 2014		9,119,000				416,913
Beginning Balance at Dec. 31, 2014	563,352	$ 96	1,148,908	(507,521)	(242)	$ (77,699)	563,542	(190)	23,071
Balance, Shares at Dec. 31, 2014		8,975,833				575,441
Net income (loss)	28,919			29,119			29,119	(200)	(182)
Net unrealized gain (loss) on securities available-for-sale	(99)				(99)		(99)
Foreign currency translation adjustments	(320)				(320)		(320)
Activity of noncontrolling interests, net									32,688
Cash dividends declared	(8,143)		(8,143)				(8,143)
Repurchases of common shares	$ (28,000)					$ (28,000)	(28,000)
Repurchases of common shares, 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, 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)	$ 55,557
Balance, Shares at Jun. 30, 2015		8,818,629				788,029