DEBT - Narrative (Details)		3 Months Ended		6 Months Ended
	Feb. 04, 2020 USD ($) $ / shares	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Feb. 03, 2020 USD ($)
Debt Instrument [Line Items]
Term loan component of senior credit facility				$ 45,000,000		$ 33,750,000
Cost of call transactions				0	$ 104,248,000
Proceeds from warrant transactions				0	44,563,000
Carrying amount, liability component				562,968,000		474,834,000
Securitization program outstanding borrowings, maximum limit				150,000,000.0
Long-term borrowings under securitization facility				$ 112,500,000		$ 112,500,000
Weighted average interest rate, accounts receivable securitization revolving loan facility				1.20%		1.30%
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Securitization facility, outstanding borrowings, fair value				$ 110,300,000
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 1,300,000,000
Line of credit facility outstanding				$ 8,800,000		$ 97,500,000
Weighted average interest rate on debt				1.50%		1.50%
Revolving Credit Facility | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Line of credit facility, fair value of amount outstanding				$ 8,600,000
Standby Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity							60,000,000
Swingline Loans
Debt Instrument [Line Items]
Maximum borrowing capacity							60,000,000
Senior Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity							2,200,000,000
Incremental financing costs capitalized							4,600,000
Previously capitalized financing costs, written-off			$ 1,200,000
Incremental financing cost expense		$ 3,300,000
Senior Credit Facility | Overnight Federal Funds
Debt Instrument [Line Items]
Interest rates available				0.50%
Senior Credit Facility | One Month Eurodollar Rate
Debt Instrument [Line Items]
Interest rates available				1.00%
Senior Credit Facility | Minimum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage				0.15%
Senior Credit Facility | Minimum | Eurodollar
Debt Instrument [Line Items]
Interest rates available				1.00%
Senior Credit Facility | Maximum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage				0.30%
Senior Credit Facility | Maximum | Eurodollar
Debt Instrument [Line Items]
Interest rates available				2.25%
Senior Credit Facility | Standby Letters of Credit
Debt Instrument [Line Items]
Line of credit facility outstanding				$ 0
Letters of credit outstanding				1,600,000		$ 1,600,000
Term Loan Facility | Secured Debt
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 877,500,000
Line of credit facility outstanding				$ 866,300,000		$ 877,500,000
Weighted average interest rate on debt				1.50%		1.50%
Term loan component of senior credit facility				$ 45,000,000.0
Term Loan Facility | Secured Debt | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Line of credit facility, fair value of amount outstanding				850,400,000
2025 Notes | Convertible Debt
Debt Instrument [Line Items]
Incremental financing costs capitalized	$ 13,200,000
Convertible notes, maximum borrowing capacity	$ 575,000,000.0			575,000,000.0		$ 575,000,000.0
Convertible notes, interest rate	0.50%
Debt proceeds, classified as equity at time of offering	$ 104,500,000
Effective interest rate	4.20%
Initial conversion rate	13.5739
Initial conversion price (in dollars per share) | $ / shares	$ 73.67
Maximum selling price of the company's common stock of the conversion price	130.00%
Maximum average conversion value of notes	98.00%
Redemption price, percentage	100.00%
Warrant strike price (in dollars per share) | $ / shares	$ 113.34
Carrying amount, liability component						485,900,000
Unamortized discount						$ 89,100,000
Fair value				630,700,000
Cash interest				$ 1,400,000
2025 Notes | Convertible Debt | Call Option
Debt Instrument [Line Items]
Cost of call transactions	$ 104,200,000
Proceeds from warrant transactions	$ 44,500,000
Initial strike price (in dollars per share) | $ / shares	$ 73.67
2020 Notes
Debt Instrument [Line Items]
Incremental financing cost expense					6,800,000
Cash interest					1,200,000
Interest expense					$ 8,000,000.0