SEGMENT INFORMATION - Summary (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) reporting_units	Sep. 30, 2019 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | reporting_units			3
Segment Reporting Information [Line Items]
Revenues	$ 1,917,815	$ 1,105,941	$ 5,493,365	$ 2,924,131
Operating income (loss)	290,419	174,037	641,971	595,255
Depreciation and amortization	406,899	183,746	1,207,392	477,498
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	(17,661)	(2,526)	(53,390)	(2,527)
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(156,414)	(153,999)	(480,730)	(261,356)
Depreciation and amortization	6,031	1,189	15,917	3,296
Acquisition-related costs	57,600	86,900	208,000	98,000
Merchant Solutions | Operating segments
Segment Reporting Information [Line Items]
Revenues	1,243,961	1,004,943	3,460,785	2,812,640
Operating income (loss)	344,981	318,786	824,212	840,326
Depreciation and amortization	238,946	156,016	708,808	447,315
Acquisition-related costs		13,900	5,700	22,300
Issuer Solutions | Operating segments
Segment Reporting Information [Line Items]
Revenues	487,409	75,628	1,461,196	86,122
Operating income (loss)	70,800	5,885	188,131	12,920
Depreciation and amortization	137,965	21,341	410,955	21,687
Business and Consumer Solutions | Operating segments
Segment Reporting Information [Line Items]
Revenues	204,106	27,896	624,774	27,896
Operating income (loss)	31,052	3,365	110,358	3,365
Depreciation and amortization	$ 23,957	$ 5,200	$ 71,712	$ 5,200