DEBT - Narrative (Details)			3 Months Ended		6 Months Ended
	Jul. 14, 2020	Feb. 04, 2020 USD ($) $ / shares	Mar. 31, 2020 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jul. 13, 2020	Feb. 03, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Term loan component of senior credit facility					$ 11,250,000				$ 45,000,000
Carrying amount, liability component					465,006,000				0
Cost of call transactions					104,248,000	$ 0
Proceeds from warrant transactions					44,563,000	$ 0
Securitization program outstanding borrowings, maximum limit				$ 150,000,000.0
Securitization program, term				3 years
Long-term borrowings under securitization facility					$ 68,700,000				$ 104,500,000
Weighted average interest rate, accounts receivable securitization revolving loan facility					1.70%				2.80%
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Securitization facility, outstanding borrowings, fair value					$ 68,500,000
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
Senior Credit Facility | First fiscal quarter ending after the Closing Date through June 30, 2022
Debt Instrument [Line Items]
Maximum consolidated total leverage ratio								5.00
Senior Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Maximum consolidated total leverage ratio	5.0
Senior Credit Facility | Subsequent Event | First fiscal quarter ending after the Closing Date through June 30, 2022
Debt Instrument [Line Items]
Maximum consolidated total leverage ratio							5.0
Senior Credit Facility | Subsequent Event | Four financial quarters beginning July 1, 2020 and ending June 30, 2021
Debt Instrument [Line Items]
Maximum consolidated total leverage ratio	5.5
Senior Credit Facility | Minimum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage					0.15%
Senior Credit Facility | Minimum | Subsequent Event | Four financial quarters beginning July 1, 2020 and ending June 30, 2021
Debt Instrument [Line Items]
Maximum consolidated total leverage ratio	5.0
Senior Credit Facility | Maximum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage					0.30%
Senior Credit Facility | Maximum | Subsequent Event | Four financial quarters beginning July 1, 2020 and ending June 30, 2021
Debt Instrument [Line Items]
Maximum consolidated total leverage ratio	5.5
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
Convertible notes, interest rate		0.50%
Debt proceeds, classified as equity at time of offering		$ 104,500,000
Effective interest rate		4.20%
Carrying amount, liability component					477,200,000
Unamortized discount					97,800,000
Fair value					522,700,000
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
Cash interest					1,200,000
Amortization of discount					6,800,000
Interest expense					8,000,000.0
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
Eurodollar | Senior Credit Facility | Minimum
Debt Instrument [Line Items]
Interest rates available					1.00%
Eurodollar | Senior Credit Facility | Maximum
Debt Instrument [Line Items]
Interest rates available					1.75%
Eurodollar | Senior Credit Facility | Maximum | Subsequent Event
Debt Instrument [Line Items]
Interest rates available	2.25%
Overnight Federal Funds | Senior Credit Facility
Debt Instrument [Line Items]
Interest rates available					0.50%
One Month Eurodollar Rate | Senior Credit Facility
Debt Instrument [Line Items]
Interest rates available					1.00%
Secured Debt | Term Loan Facility
Debt Instrument [Line Items]
Maximum borrowing capacity								$ 877,500,000
Line of credit facility outstanding					$ 877,500,000				$ 877,500,000
Weighted average interest rate on debt					1.60%				3.20%
Term loan component of senior credit facility					$ 11,300,000
Secured Debt | Term Loan Facility | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Line of credit facility, fair value of amount outstanding					820,000,000.0
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity								1,300,000,000
Line of credit facility outstanding					$ 150,000,000.0				$ 375,000,000.0
Weighted average interest rate on debt					1.60%				3.20%
Revolving Credit Facility | Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Line of credit facility, fair value of amount outstanding					$ 139,300,000
Standby Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity								60,000,000
Standby Letters of Credit | Senior Credit Facility
Debt Instrument [Line Items]
Line of credit facility outstanding					0
Letters of credit outstanding					$ 800,000				$ 800,000
Swingline Loans
Debt Instrument [Line Items]
Maximum borrowing capacity								$ 60,000,000