Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total		Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Stockholders' Equity beginning balance at Dec. 31, 2017	$ 3,676,522		$ 122	$ 2,214,224	$ 2,958,921	$ (551,857)	$ (944,888)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	174,937				174,937
Other comprehensive income from currency, net of tax	43,254					43,254
Acquisition of common stock	(88,292)			0			(88,292)
Share-based compensation	14,403			14,403
Issuance of common stock	19,976		1	19,975
Stockholders' Equity ending balance at Mar. 31, 2018	3,888,052		123	2,248,602	3,181,110	(508,603)	(1,033,180)
Stockholders' Equity beginning 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]
Net income	172,107	[1]			172,107
Other comprehensive income from currency, net of tax	(20,334)					(20,334)
Acquisition of common stock	(3,322)			33,000			(36,322)
Share-based compensation	12,541			12,541
Issuance of common stock	29,795			29,795
Stockholders' Equity ending balance at Mar. 31, 2019	$ 3,530,967	[2]	$ 123	$ 2,382,179	$ 3,989,763	$ (934,192)	$ (1,906,906)

[1] Reflects the impact of the Company's adoption of Accounting Standards Update 2016-18, "Statement of Cash Flows (Topic 230)", which was adopted by the Company on January 1, 2018 and applied retrospectively to results for 2017. The adoption of Topic 230 resulted in the statement of cash flows presenting the changes in the total of cash, cash equivalents and restricted cash. As a result, the Company will no longer present transfers between cash and cash equivalents and restricted cash in the statement of cash flows.

[2] Reflects the impact of the Company's adoption of ASU 2016-02 "Leases", on January 1, 2019, using the modified retrospective transition method. Under this method, financial results reported in periods prior to 2019 are unchanged. Refer to footnote 2.