Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 106,570	$ 34,579	$ 59,894	$ 26,344	$ 346,695	$ 232,131	$ 156,940
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization					111,744	106,021	95,030
Share-based compensation					21,439	16,764	15,618
Unrealized foreign exchange (gain) loss, net					(2,701)	26,655	(20,300)
Goodwill and Intangible Asset Impairment					0	7,049	34,056	$ 34,056
Deferred income taxes					17,113	2,425	(10,861)
Loss on early retirement of debt					9,831	0	0
Loss (income) from unconsolidated affiliates					0	117	(48)
Accretion of convertible debt discount and amortization of debt issuance costs					17,088	14,121	13,504
Changes in working capital, net of amounts acquired:
Income taxes payable, net					13,177	(13,317)	23,183
Trade accounts receivable					(87,882)	26,497	(198,089)
Prepaid expenses and other current assets					(68,945)	(29,066)	35,451
Trade accounts payable					53,550	45,562	3,840
Deferred revenue					132	9,349	3,724
Accrued expenses and other current liabilities					98,459	(37,595)	106,350
Changes in noncurrent assets and liabilities					(25,212)	(9,480)	27,878
Net cash provided by operating activities					504,488	397,233	286,276
Cash flows from investing activities:
Acquisitions, net of cash acquired					(94,187)	(12,854)	0
Purchases of property and equipment					(131,287)	(112,484)	(97,235)
Purchases of other long-term assets					(7,274)	(8,528)	(6,039)
Other, net					3,721	1,583	1,416
Net cash used in investing activities					(229,027)	(132,283)	(101,858)
Cash flows from financing activities:
Proceeds from issuance of shares					14,979	18,608	10,990
Repurchase of shares					(74,456)	(177,855)	(3,065)
Borrowings from revolving credit agreements					2,498,298	5,773,294	2,409,203
Repayments of revolving credit agreements					(2,714,203)	(5,560,089)	(2,566,621)
Repayments of long-term debt obligations					(446,702)	(52,199)	(8,907)
Repayments of capital lease obligations					(6,474)	(6,137)	(4,883)
Net borrowing (repayments of) from short-term debt obligations					(32,091)	9,472	1,853
Proceeds from Issuance of Long-term Debt					1,194,900	0	0
Payments of Debt Issuance Costs					17,947	3,071	0
Other, net					(6)	1	281
Net cash provided by (used in) financing activities					416,298	2,024	(161,149)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents					(5,332)	(36,540)	65,161
Increase in cash and cash equivalents and restricted cash					686,427	230,434	88,430
Cash and cash equivalents and restricted cash at beginning of period		$ 1,130,952		$ 900,518	1,130,952	900,518	812,088
Cash and cash equivalents and restricted cash at end of period	1,817,379		1,130,952		1,817,379	1,130,952	900,518	$ 812,088
Cash and cash equivalents	786,081		385,031		786,081	385,031	280,128
Restricted Cash	34,301		31,237		34,301	31,237	32,185
CashinATM	665,641		395,378		665,641	395,378	253,847
SettlementAssetsCashandCashEquivalent	282,188		273,948		282,188	273,948	285,169
SettlementAssetsRestrictedCash	$ 49,168		$ 45,358		49,168	45,358	49,189
Interest paid during the period					13,125	23,554	20,457
Income taxes paid during the period					74,086	84,382	48,644
Other Significant Noncash Transaction, Value of Consideration Received					$ 0	$ 0	$ 0