INDEBTEDNESS - Convertible Note Hedge and Warrant Transactions Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	Nov. 13, 2020	Mar. 05, 2020
Convertible Debt
Debt Instrument [Line Items]
Conversion price of convertible debt (in USD per share)		$ 121.01
Conversion price of convertible debt after effect of warrants and note hedge (in USD per share)		$ 161.34
Convertible Debt \| 2027 Convertible Notes
Debt Instrument [Line Items]
Conversion price of convertible debt (in USD per share)	$ 299.13
Conversion price of convertible debt after effect of warrants and note hedge (in USD per share)	414.18
Convertible Debt \| 2026 Convertible Notes
Debt Instrument [Line Items]
Conversion price of convertible debt (in USD per share)	299.13
Conversion price of convertible debt after effect of warrants and note hedge (in USD per share)	$ 368.16
Common Stock Warrant, 2027 Notes
Debt Instrument [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)	1,900
Exercise price of warrants (in USD per share)	$ 414.18
Proceeds from issuance of senior notes	$ 68.0
Common Stock Warrant, 2026 Notes
Debt Instrument [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)	1,900
Exercise price of warrants (in USD per share)	$ 368.16
Proceeds from issuance of senior notes	$ 64.6
Common Stock Warrant, 2025 Notes
Debt Instrument [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)		8,260
Exercise price of warrants (in USD per share)		$ 161.34
Proceeds from issuance of senior notes		$ 99.5
Options Held
Debt Instrument [Line Items]
Outstanding warrants to purchase aggregate shares of capital stock (in shares)	1,900	8,300
Convertible note hedge, option to purchase common stock, price (in USD per share)	$ 299.13	$ 121.01
Cost of convertible note hedge		$ 149.2
Options Held \| 2027 Convertible Notes
Debt Instrument [Line Items]
Cost of convertible note hedge	$ 104.3
Options Held \| 2026 Convertible Notes
Debt Instrument [Line Items]
Cost of convertible note hedge	$ 84.6

Debt Instrument, Convertible, Conversion Price, Effective After Hedging Transactions

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Derivative, Price Risk Option Strike Price Per Share

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Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

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