Condensed Consolidated Statements of Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid - in Capital [Member]	Retained Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
BALANCE at Dec. 31, 2014	$ (659,641)	$ 84	$ 2,155,864	$ (2,772,775)	$ (37,506)	$ (5,308)
BALANCE, shares at Dec. 31, 2014		84,179,806
Net income	130,081			130,081
Dividends declared (cash dividend of $0.45 per share)	(38,369)			(38,369)
Foreign currency translation adjustment, net	(21,718)				(21,718)
Purchase of stock at cost	(59,957)					(59,957)
Purchase of stock at cost, shares		(2,000,000)
Executive Deferred Compensation Plan activity	4,042		4,042
Executive Deferred Compensation Plan activity, shares		49,307
Shares issued from the Employee Stock Purchase Plan	3,745		3,745
Shares issued from the Employee Stock Purchase Plan, shares		131,865
Stock options exercised including related tax benefits	5,632	$ 1	5,631
Stock options exercised including related tax benefits, shares		251,943
Issuance of shares	(198)		(198)
Issuance of shares, shares		16,042
Share-based compensation	10,461		10,461
BALANCE at Jun. 30, 2015	(625,922)	$ 85	2,179,545	(2,681,063)	(59,224)	(65,265)
BALANCE, shares at Jun. 30, 2015		82,628,963
BALANCE at Dec. 31, 2015	(552,138)	$ 85	2,193,193	(2,607,415)	(72,736)	(65,265)
BALANCE, shares at Dec. 31, 2015		83,366,888
Net income	77,534			77,534
Dividends declared (cash dividend of $0.45 per share)	(38,187)			(38,187)
Foreign currency translation adjustment, net	(5,398)				(5,398)
Purchase of stock at cost	$ (21,961)					(21,961)
Purchase of stock at cost, shares	(1,000,000)	(1,000,000)
Executive Deferred Compensation Plan activity	$ 1,522		1,522
Executive Deferred Compensation Plan activity, shares		12,964
Shares issued from the Employee Stock Purchase Plan	3,460	$ 1	3,459
Shares issued from the Employee Stock Purchase Plan, shares		182,285
Stock options exercised including related tax benefits	649		649
Stock options exercised including related tax benefits, shares		29,475
Issuance of shares	(63)		(63)
Issuance of shares, shares		23,975
Share-based compensation	12,150		12,150
BALANCE at Jun. 30, 2016	$ (522,432)	$ 86	$ 2,210,910	$ (2,568,068)	$ (78,134)	$ (87,226)
BALANCE, shares at Jun. 30, 2016		82,615,587