DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Prior Period Adjustments (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2020
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating activities	$ 229,423	$ (29,193)
Investing activities	1,130,613	(158,023)
Financing activities	(968,556)	1,119,588
Effect of foreign exchange rate on cash and cash equivalents	(948)	(8,206)
Net increase in cash, cash equivalents, restricted cash, and customer funds	390,532	924,166
Cash, cash equivalents, restricted cash, and customer funds, beginning of period	6,975,090	4,793,171
Cash, cash equivalents, restricted cash, and customer funds, end of period	$ 7,365,622	5,717,337	$ 4,793,171
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating activities			(97,741)
Investing activities			(158,023)
Financing activities			180,992
Effect of foreign exchange rate on cash and cash equivalents			(8,206)
Net increase in cash, cash equivalents, restricted cash, and customer funds			(82,978)
Cash, cash equivalents, restricted cash, and customer funds, beginning of period		3,201,863
Cash, cash equivalents, restricted cash, and customer funds, end of period		3,118,885	3,201,863
Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating activities		68,548
Investing activities		0
Financing activities		938,596
Effect of foreign exchange rate on cash and cash equivalents		0
Net increase in cash, cash equivalents, restricted cash, and customer funds		1,007,144
Cash, cash equivalents, restricted cash, and customer funds, beginning of period		1,591,308
Cash, cash equivalents, restricted cash, and customer funds, end of period		$ 2,598,452	$ 1,591,308

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of increase (decrease) in cash, cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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