Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total		Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2015	$ 2,830,047		$ 121	$ 1,988,917	$ 1,766,336	$ (570,811)	$ (354,516)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	452,385	[1]			452,385
Other comprehensive income (loss), net of tax	(95,592)					(95,592)
Acquisition of common stock	(187,979)			0			(187,979)
Issuance of common stock	85,177		0	85,177
Ending Balance at Dec. 31, 2016	3,084,038		121	2,074,094	2,218,721	(666,403)	(542,495)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	740,200	[1]			740,200
Other comprehensive income (loss), net of tax	114,546					114,546
Acquisition of common stock	(402,393)			0			(402,393)
Issuance of common stock	140,131		1	140,130
Ending 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	811,483	[1],[2]			811,483
Other comprehensive income (loss), net of tax	(362,001)
Other comprehensive income from currency, net of tax of $0	(362,001)					(362,001)
Acquisition of common stock	(958,696)			(33,000)			(925,696)
Issuance of common stock	125,620		1	125,619
Ending Balance at Dec. 31, 2018	$ 3,340,180	[3]	$ 123	$ 2,306,843	$ 3,817,656	$ (913,858)	$ (1,870,584)

[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 Accounting Standards Update 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASC 606") and related cost capitalization guidance, which was adopted by the Company on January 1, 2018 using the modified retrospective transition method. The adoption of ASC 606 resulted in an adjustment to retained earnings in our consolidated balance sheet for the cumulative effect of applying the standard, which included costs incurred to obtain a contract, as well as presentation changes in our statements of income, including the classification of certain amounts previously classified as merchant commissions and processing expense net with revenues. As a result of the application of the modified retrospective transition method, the Company's prior period results within its Form 10-K and quarterly reports on Form 10-Q will not be restated to reflect ASC 606.

[3] Reflects the impact of the Company's adoption of ASC 606 and related cost capitalization guidance, which was adopted by the Company on January 1, 2018 using the modified retrospective transition method. The adoption of ASC 606 resulted in an adjustment to retained earnings in our consolidated balance sheet for the cumulative effect of applying the standard, which included costs incurred to obtain a contract, as well as presentation changes in our statements of income, including the classification of certain amounts previously classified as merchant commissions and processing expense net with revenues. As a result of the application of the modified retrospective transition method, the Company's prior period results within its Form 10-K and quarterly reports on Form 10-Q will not be restated to reflect ASC 606.