Adjustments to Additional Paid in Capital, Warrants Settled

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Debt Instrument, Convertible, Increase (Decrease) If-Converted Value in Excess of Principal

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Debt Instrument, Convertible, Maximum Threshold Percentage of Debt Trading Price Trigger

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Exercise Price of Convertible Bond Hedge

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Payments for Convertible Bond Hedges

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Warrants Settled

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No definition available.

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Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital.

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Amount of increase in additional paid in capital (APIC) resulting from the issuance of warrants. Includes allocation of proceeds of debt securities issued with detachable stock purchase warrants.

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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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Number of warrants or rights outstanding.

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Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Amount of a favorable spread to a debt holder between the amount of debt being converted and the value of the securities received upon conversion. This is an embedded conversion feature of convertible debt issued that is in-the-money at the commitment date.

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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The amount by which the convertible debt's if-converted value exceeds its principle amount at the balance sheet date, regardless of whether the instrument is currently convertible. This element applies to public companies only.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

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Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

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Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

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Face (par) amount of debt instrument at time of issuance.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after accumulated amortization, of debt premium.

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Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The increase (decrease) during the period in the carrying value of derivative instruments reported as assets that are due to be disposed of within one year (or the normal operating cycle, if longer).

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The increase (decrease) during the period in the carrying value of derivative instruments reported as liabilities that are due to be disposed of within one year (or the normal operating cycle, if longer).

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The aggregate amount paid by the entity to reacquire the right to purchase equity shares at a predetermined price, usually issued together with corporate debt.

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The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

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The cash inflow provided by derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments.

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The cash outflow for a borrowing supported by a written promise to pay an obligation.

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Convertible Senior Notes - Narrative (Details)				1 Months Ended					2 Months Ended			12 Months Ended
Convertible Senior Notes - Narrative (Details)	Aug. 15, 2019 USD ($)	Dec. 31, 2018 USD ($) shares	May 22, 2018 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Nov. 30, 2018 shares	Jun. 19, 2018 USD ($)	May 31, 2018 trading_day	Aug. 31, 2014 USD ($) trading_day day $ / shares shares	Nov. 30, 2018 USD ($)	Aug. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Warrants issued in public offering (shares) \| shares								3,264,643
Exercise price of convertible bond hedge (USD per share) \| $ / shares								$ 75.05
Derivative asset		$ 22,576,000										$ 0	$ 22,576,000
Net change in fair value of derivatives													1,800,000
Warrant exercise price (USD per share) \| $ / shares								$ 125.08
Value of warrants issued								$ 11,600,000
Debt issuance costs related to the equity component of convertible debt													18,859,000	$ 10,704,000
Convertible debt, noncurrent		$ 609,864,000										638,959,000	609,864,000
Warrants settled (in shares) \| shares					525,000
Deduction to additional paid-in-capital for warrants settled												28,300,000
Payments for repurchase of warrants												$ 380,000	30,094,000	$ 0
Gain (loss) on derivative liabilities													$ (1,800,000)
Warrants outstanding (in shares) \| shares		2,739,643										1,890,359	2,739,643
2023 Convertible Senior Notes
Debt Instrument [Line Items]
Value of warrants issued													$ 97,805,000
Convertible Notes \| 2019 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding		$ 27,326,000						245,000,000.0				$ 0	27,326,000
Net proceeds from debt issuance								$ 239,300,000
Effective rate (as a percent)								5.83%
Convertible debt conversion ratio								0.0133251
Debt conversion price per share (USD per share) \| $ / shares								$ 75.05
Interest on debt instrument (as a percent)								0.75%
If-converted value in excess of principal		23,400,000	$ 341,600,000
Increase (decrease) in if-converted value in excess of principal												118,700,000
Notices for conversion				$ 1,000,000.0						$ 195,900,000	$ 21,800,000
Conversion value over the principal amount				$ 500,000					$ 439,600,000		$ 31,600,000
Repayments of notes	$ 26,300,000
Gain (loss) on extinguishment of debt												(3,200,000)
Payments for convertible bond hedges								$ 48,100,000
Derivative asset		22,600,000	340,000,000.0										22,600,000
Net change in fair value of derivatives												11,000,000.0	(119,400,000)
Proceeds from derivative instrument													471,200,000
Debt issuance costs related to the liability component of convertible debt	$ 11,900,000
Gain (loss) on derivative liabilities												(11,000,000.0)	119,400,000
Convertible Notes \| 2019 Convertible Senior Notes \| Redemption Period One
Debt Instrument [Line Items]
Number of trading days \| trading_day								20
Number of consecutive trading days \| trading_day								30
Stock price trigger to classify convertible debt as current (as a percent)								130.00%
Convertible Notes \| 2019 Convertible Senior Notes \| Redemption Period Two
Debt Instrument [Line Items]
Number of trading days \| day								5
Number of consecutive trading days \| trading_day								10
Maximum threshold of debt trading price trigger (as a percent)								98.00%
Convertible Notes \| 2023 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding		$ 750,000,000	750,000,000									750,000,000	$ 750,000,000
Net proceeds from debt issuance			$ 733,100,000
Convertible debt conversion ratio							0.0040244
Debt conversion price per share (USD per share) \| $ / shares			$ 248.48
Interest on debt instrument (as a percent)			0.75%
Warrants issued in public offering (shares) \| shares			3,018,327
Payments for convertible bond hedges			$ 140,300,000
Warrant exercise price (USD per share) \| $ / shares			$ 315.38
Value of warrants issued			$ 90,000,000.0
Fair value of the conversion option derivative liability			144,000,000.0
Debt issuance costs			16,900,000
Debt issuance costs related to the equity component of convertible debt												3,200,000
Debt issuance costs related to the liability component of convertible debt			$ 13,700,000
Increase (decrease) in derivative assets												19,200,000
Increase (decrease) in derivative liabilities						$ 13,500,000						7,500,000
Convertible Notes \| 2023 Convertible Senior Notes \| Redemption Period One
Debt Instrument [Line Items]
Number of trading days \| trading_day							20
Number of consecutive trading days \| trading_day							30
Stock price trigger to classify convertible debt as current (as a percent)							130.00%
Convertible Notes \| 2023 Convertible Senior Notes \| Redemption Period Two
Debt Instrument [Line Items]
Number of trading days \| trading_day							5
Number of consecutive trading days \| trading_day							10
Maximum threshold of debt trading price trigger (as a percent)							98.00%
Other Expense \| Convertible Notes \| 2019 Convertible Senior Notes
Debt Instrument [Line Items]
Net change in fair value of derivatives												10,200,000
Gain (loss) on derivative liabilities												$ (10,200,000)