CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2018	$ 666,901	$ 441,369	$ 1,812,682	$ (2,354,617)	$ 1,626,693	$ (859,226)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(176,296)				(176,296)
Other comprehensive (loss) income, net of tax	21,292					21,292
Issuance of treasury stock for restricted stock units vesting	(387)		(1,829)	1,442
Share-based compensation	11,865		11,865
Ending balance at Mar. 31, 2019	523,375	441,369	1,822,718	(2,353,175)	1,450,397	(837,934)
Beginning balance at Dec. 31, 2018	666,901	441,369	1,812,682	(2,354,617)	1,626,693	(859,226)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(213,687)
Other comprehensive (loss) income, net of tax	(21,595)
Ending balance at Sep. 30, 2019	463,756	441,369	1,811,214	(2,321,012)	1,413,006	(880,821)
Beginning balance at Mar. 31, 2019	523,375	441,369	1,822,718	(2,353,175)	1,450,397	(837,934)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(107,987)				(107,987)
Other comprehensive (loss) income, net of tax	(1,728)					(1,728)
Issuance of treasury stock for restricted stock units vesting	(35)		(3,060)	3,025
Deferred compensation	125		(151)	276
Share-based compensation	12,445		12,445
Ending balance at Jun. 30, 2019	426,195	441,369	1,831,952	(2,349,874)	1,342,410	(839,662)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	70,596				70,596
Other comprehensive (loss) income, net of tax	(41,159)					(41,159)
Issuance of treasury stock for restricted stock units vesting	(6,707)		(35,569)	28,862
Share-based compensation	14,831		14,831
Ending balance at Sep. 30, 2019	463,756	441,369	1,811,214	(2,321,012)	1,413,006	(880,821)
Beginning balance at Dec. 31, 2019	491,714	441,369	1,825,569	(2,318,921)	1,413,181	(869,484)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(210,741)				(210,741)
Other comprehensive (loss) income, net of tax	(136,399)					(136,399)
Issuance of treasury stock for restricted stock units vesting	(966)		(3,777)	2,811
Share-based compensation	14,275		14,275
Ending balance at Mar. 31, 2020	157,883	441,369	1,836,067	(2,316,110)	1,202,440	(1,005,883)
Beginning balance at Dec. 31, 2019	491,714	441,369	1,825,569	(2,318,921)	1,413,181	(869,484)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(3,919)
Other comprehensive (loss) income, net of tax	(116,390)
Ending balance at Sep. 30, 2020	404,507	441,369	1,823,742	(2,283,992)	1,409,262	(985,874)
Beginning balance at Mar. 31, 2020	157,883	441,369	1,836,067	(2,316,110)	1,202,440	(1,005,883)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(109,172)				(109,172)
Other comprehensive (loss) income, net of tax	28,286					28,286
Issuance of treasury stock for restricted stock units vesting	(111)		(944)	833
Deferred compensation	124		(186)	310
Share-based compensation	9,138		9,138
Ending balance at Jun. 30, 2020	86,148	441,369	1,844,075	(2,314,967)	1,093,268	(977,597)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	315,994				315,994
Other comprehensive (loss) income, net of tax	(8,277)					(8,277)
Issuance of treasury stock for restricted stock units vesting	(5,890)		(36,865)	30,975
Share-based compensation	16,532		16,532
Ending balance at Sep. 30, 2020	$ 404,507	$ 441,369	$ 1,823,742	$ (2,283,992)	$ 1,409,262	$ (985,874)