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Convertible Senior Notes - Narrative (Details) |  |  |  |  | 1 Months Ended | 2 Months Ended | 12 Months Ended
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Jan. 28, 2021 USD ($) | Aug. 15, 2019 USD ($) | Dec. 31, 2018 USD ($) | May 22, 2018 USD ($) $ / shares shares | Apr. 30, 2020 USD ($) | Jun. 30, 2019 USD ($) | Nov. 30, 2018 shares | Jun. 19, 2018 USD ($) | May 31, 2018 trading_day | Aug. 31, 2014 USD ($) day trading_day $ / shares shares | Nov. 30, 2018 USD ($) | Aug. 31, 2018 USD ($) | Apr. 30, 2018 USD ($) | Dec. 31, 2020 USD ($) $ / shares shares | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net change in fair value of derivatives |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,800,000
Warrants issued in public offering (shares) | shares |  |  |  |  |  |  |  |  |  | 3,264,643 |  |  |  |  |  |
Exercise price of convertible bond hedge (USD per share) | $ / shares |  |  |  |  |  |  |  |  |  | $ 75.05 |  |  |  |  |  |
Gain (loss) on derivative liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (1,800,000)
Warrant exercise price (USD per share) | $ / shares |  |  |  |  |  |  |  |  |  | $ 125.08 |  |  |  | $ 1.50 |  |
Value of warrants issued |  |  |  |  |  |  |  |  |  | $ 11,600,000 |  |  |  |  |  |
Warrants settled (shares) | shares |  |  |  |  |  |  | 525,000 |  |  |  |  |  |  |  |  |
Deduction to additional paid-in-capital for warrants settled |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 28,300,000
Payments for repurchase of warrants |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 | $ 380,000 | 30,094,000
Warrants outstanding (shares) | shares |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |
Debt issuance costs related to the equity component of convertible debt |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (3,236,000) |  |
2023 Convertible Senior Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Value of warrants issued |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 97,805,000
Convertible Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Face amount of debt instrument |  |  |  |  |  |  |  |  |  |  |  |  |  | 495,280,000 | 750,000,000 |
Total long-term portion of notes payable |  |  |  |  |  |  |  |  |  |  |  |  |  | 442,293,000 | 638,959,000 |
Convertible Notes | 2019 Convertible Senior Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Face amount of debt instrument |  |  |  |  |  |  |  |  |  | 245,000,000.0 |  |  |  |  |  |
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 |  |  |
Gain (loss) on extinguishment of debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (3,200,000) |
Repayments of notes |  | $ 26,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt issuance costs related to the liability component of convertible debt |  | $ 11,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net change in fair value of derivatives |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 11,000,000.0 | (119,400,000)
Payments for convertible bond hedges |  |  |  |  |  |  |  |  |  | $ 48,100,000 |  |  |  |  |  |
Current derivative asset |  |  |  | 340,000,000.0 |  |  |  |  |  |  |  |  |  |  | 22,600,000 |
Gain (loss) on derivative liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (11,000,000.0) | $ 119,400,000
Proceeds from derivative instrument |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 471,200,000 |
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] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Face amount of debt instrument |  |  |  | 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% |  |  |  |  |  |  |  |  |  |  |  |
Debt issuance costs related to the liability component of convertible debt |  |  |  | $ 13,700,000 |  |  |  |  |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in derivative liabilities |  |  |  |  |  |  |  | $ 13,500,000 |  |  |  |  |  |  | 7,500,000 |
Debt issuance costs |  |  |  | $ 16,900,000 |  |  |  |  |  |  |  |  |  |  |  |
Debt issuance costs related to the equity component of convertible debt |  |  |  |  |  |  |  |  |  |  |  |  |  | (3,200,000) | 3,200,000 |
Repurchased face amount of debt instrument |  |  |  |  | $ 234,400,000 |  |  |  |  |  |  |  |  | 254,700,000 |  |
Repayments of senior debt |  |  |  |  | 203,800,000 |  |  |  |  |  |  |  |  | 222,800,000 |  |
Accrued interest on repurchased debt |  |  |  |  | $ 600,000 |  |  |  |  |  |  |  |  | 600,000 |  |
Loss on repurchase of debt instrument |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,500,000 |  |
Reduction in debt discount |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 35,000,000.0 |  |
Increase (decrease) in derivative assets |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 19,200,000 |
Convertible Notes | 2023 Convertible Senior Notes | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repurchased face amount of debt instrument | $ 20,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayments of senior debt | 19,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Accrued interest on repurchased debt | $ 100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
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) |

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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 25 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=51819886&loc=SL6014347-161799 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109126253&loc=d3e4724-112606 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031898-161870 + Details
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- Definition 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. + References No definition available. + Details
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- Definition 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. + References No definition available. + Details
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