CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Accumulated Foreign Currency Adjustment Attributable to Parent	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at beginning of period at Dec. 31, 2015	$ 2,628,755	$ (704,404)	$ 441,369	$ 1,789,870	$ (2,494,901)	$ 3,741,316	$ (848,899)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	312,908					312,908
Other comprehensive loss, net of tax	(94,130)	(101,539)					(94,130)
Issuance of treasury stock for stock option exercises	34,055			(3,854)	37,909
Issuance of treasury stock for restricted stock units vesting	(17,848)			(47,516)	29,668
Deferred compensation	385			385	575	(575)
Share-based compensation	53,950			53,950
Dividend equivalents for restricted stock units	(1,377)			(2,003)		626
Dividends	(518,529)					(518,529)
Balance at end of period at Dec. 31, 2016	2,398,169	(805,943)	441,369	1,790,832	(2,426,749)	3,535,746	(943,029)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(879,286)
Other comprehensive loss, net of tax	80,497
Balance at end of period at Sep. 30, 2017	1,323,329
Balance at beginning of period at Dec. 31, 2016	2,398,169	(805,943)	441,369	1,790,832	(2,426,749)	3,535,746	(943,029)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(1,054,579)					(1,054,579)
Other comprehensive loss, net of tax	161,243	191,267					161,243
Issuance of treasury stock for stock option exercises	1,775			(286)	2,061
Issuance of treasury stock for restricted stock units vesting	(14,351)			(48,528)	34,177
Deferred compensation	(34)			(288)	634	(380)
Share-based compensation	67,119			67,119
Dividend equivalents for restricted stock units	(270)			(458)		188
Dividends	(311,973)					(311,973)
Balance at end of period at Dec. 31, 2017	1,247,099	(614,676)	441,369	1,808,391	(2,389,877)	2,169,002	(781,786)
Balance at beginning of period at Sep. 30, 2017	1,323,329
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(175,293)
Balance at end of period at Dec. 31, 2017	1,247,099	(614,676)	441,369	1,808,391	(2,389,877)	2,169,002	(781,786)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (Loss) Income	(533,299)					(533,299)
Other comprehensive loss, net of tax	(77,440)	(106,651)					(77,440)
Issuance of treasury stock for restricted stock units vesting	(9,488)			(44,547)	35,059
Deferred compensation	124			(77)	201
Share-based compensation	48,915			48,915
Dividend equivalents for restricted stock units	41					41
Balance at end of period at Dec. 31, 2018	$ 656,803	$ (721,327)	$ 441,369	$ 1,812,682	$ (2,354,617)	$ 1,616,595	$ (859,226)