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, 2019	$ 508,564	$ 441,369	$ 1,825,569	$ (2,318,921)	$ 1,430,031	$ (869,484)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(205,702)				(205,702)
Other comprehensive income (loss), 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	179,772	441,369	1,836,067	(2,316,110)	1,224,329	(1,005,883)
Beginning balance at Dec. 31, 2019	508,564	441,369	1,825,569	(2,318,921)	1,430,031	(869,484)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(5,473)
Other comprehensive income (loss), net of tax	(116,390)
Ending balance at Sep. 30, 2020	419,803	441,369	1,823,742	(2,283,992)	1,424,558	(985,874)
Beginning balance at Mar. 31, 2020	179,772	441,369	1,836,067	(2,316,110)	1,224,329	(1,005,883)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(111,109)				(111,109)
Other comprehensive income (loss), 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	106,100	441,369	1,844,075	(2,314,967)	1,113,220	(977,597)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	311,338				311,338
Other comprehensive income (loss), 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	419,803	441,369	1,823,742	(2,283,992)	1,424,558	(985,874)
Beginning balance at Dec. 31, 2020	610,144	441,369	1,842,680	(2,282,939)	1,553,610	(944,576)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(112,385)				(112,385)
Other comprehensive income (loss), net of tax	(16,450)					(16,450)
Issuance of treasury stock for stock option exercises	1,110		(803)	1,913
Issuance of treasury stock for restricted stock units vesting	(6,966)		(20,031)	13,065
Share-based compensation	15,112		15,112
Ending balance at Mar. 31, 2021	490,565	441,369	1,836,958	(2,267,961)	1,441,225	(961,026)
Beginning balance at Dec. 31, 2020	610,144	441,369	1,842,680	(2,282,939)	1,553,610	(944,576)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	677,154
Other comprehensive income (loss), net of tax	(6,075)
Ending balance at Sep. 30, 2021	1,313,678	441,369	1,821,106	(2,228,910)	2,230,764	(950,651)
Beginning balance at Mar. 31, 2021	490,565	441,369	1,836,958	(2,267,961)	1,441,225	(961,026)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(5,537)				(5,537)
Other comprehensive income (loss), net of tax	25,710					25,710
Issuance of treasury stock for stock option exercises	2,154		(676)	2,830
Issuance of treasury stock for restricted stock units vesting	(529)		(3,212)	2,683
Deferred compensation	188		(37)	225
Share-based compensation	15,168		15,168
Ending balance at Jun. 30, 2021	527,719	441,369	1,848,201	(2,262,223)	1,435,688	(935,316)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	795,076				795,076
Other comprehensive income (loss), net of tax	(15,335)					(15,335)
Issuance of treasury stock for stock option exercises	2,258		(1,585)	3,843
Issuance of treasury stock for restricted stock units vesting	(12,252)		(41,722)	29,470
Share-based compensation	16,212		16,212
Ending balance at Sep. 30, 2021	$ 1,313,678	$ 441,369	$ 1,821,106	$ (2,228,910)	$ 2,230,764	$ (950,651)