Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total		Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2017	$ 3,676,522		$ 47,252	$ 122	$ 2,214,224	$ 2,958,921	$ 47,252	$ (551,857)	$ (944,888)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	811,483	[1],[2]				811,483
Other comprehensive loss, net of tax	(362,001)							(362,001)
Acquisition of common stock	(958,696)				(33,000)				(925,696)
Share-based compensation expense	69,939				69,939
Issuance of common stock	55,681			1	55,680
Other comprehensive income, net of tax	(362,001)
Ending Balance at Dec. 31, 2018	3,340,180			123	2,306,843	3,817,656		(913,858)	(1,870,584)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income from foreign exchange, tax	0
Net income	895,073					895,073
Other comprehensive loss, net of tax	(58,607)							(58,607)
Acquisition of common stock	(694,909)				(42,000)				(652,909)
Share-based compensation expense	60,953				60,953
Issuance of common stock	168,926			1	168,925
Other comprehensive income, net of tax	(58,607)
Ending Balance at Dec. 31, 2019	3,711,616			124	2,494,721	4,712,729		(972,465)	(2,523,493)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income from foreign exchange, tax	0
Net income	704,216					704,216
Other comprehensive loss, net of tax	(390,693)							(390,693)
Acquisition of common stock	(849,909)				75,000				(924,909)
Share-based compensation expense	43,384				43,384
Issuance of common stock	136,797			2	136,795
Other comprehensive income, net of tax	(390,693)
Ending Balance at Dec. 31, 2020	$ 3,355,411			$ 126	$ 2,749,900	$ 5,416,945		$ (1,363,158)	$ (3,448,402)

[1] The Company applied the modified retrospective transition method when adopting ASU 2016-02 "Leases", therefore the Company's 2018 prior results were not restated to reflect ASU 2016-02. Refer to footnote 14.

[2] The Company applied the modified retrospective transition method when adopting ASU 2016-02 "Leases", therefore the Company's 2018 prior results were not restated to reflect ASU 2016-02. Refer to footnote 14.