Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	[1]	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues, net		$ 2,433,492		$ 2,249,538	$ 1,831,546
Expenses:
Merchant commissions		0		113,133	104,345
Processing		487,695		429,613	355,414
Selling		182,593		170,717	131,443
General and administrative		389,172		387,694	283,625
Depreciation and amortization		274,609		264,560	203,256
Other operating expense (income), net		8,725		61	(690)
Operating income		1,090,698		883,760	754,153
Investment loss	[2]	7,147		53,164	36,356
Other (income) expense, net		(152,166)		(173,436)	2,982
Interest expense, net		138,494		107,146	71,896
Loss on extinguishment of debt	[2]	2,098		3,296	0
Total other (income) expense		(4,427)		(9,830)	111,234
Income before income taxes		1,095,125		893,590	642,919
Provision for income taxes		283,642		153,390	190,534
Net income	[2]	$ 811,483		$ 740,200	$ 452,385
Earnings per share:
Basic earnings per share (in usd per share)		$ 9.14		$ 8.12	$ 4.89
Diluted earnings per share (in usd per share)		$ 8.81		$ 7.91	$ 4.75
Weighted average shares outstanding:
Basic (in shares)		88,750		91,129	92,597
Diluted (in shares)		92,151		93,594	95,213

[1] 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.

[2] 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.