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Convertible Senior Notes - Additional Information (Detail) $ / shares in Units, $ in Thousands |  | 9 Months Ended
--- | --- | ---
May 02, 2017 USD ($) | Sep. 30, 2017 USD ($) d $ / shares
Debt Instrument [Line Items] |  |
Convertible senior notes principal amount |  | $ 517,500
Proceeds from Senior Convertible Notes |  | $ 502,781
2.25% Convertible Senior Notes due 2024 |  |
Debt Instrument [Line Items] |  |
Convertible senior notes principal amount | $ 517,500 |
Convertible senior notes interest percentage | 2.25% |
Convertible senior notes convertible latest date |  | May 15, 2024
Convertible senior notes interest rate | 2.25% |
Proceeds from Senior Convertible Notes | $ 502,800 |
Threshold common stock trading days | d |  | 20
Threshold consecutive common stock trading days | d |  | 30
Threshold percentage of common stock price trigger |  | 130.00%
Minimum percentage of common stock price trigger |  | 98.00%
Conversion Observation Period |  | 25 days
Convertible senior notes convertible in to shares |  | 0.00131711
Convertible senior notes conversion price | $ / shares |  | $ 75.92
Market Price of Common stock | $ / shares |  | $ 53.28
Convertible senior note premium |  | 42.50%
Convertible senior notes redemption rate |  | 100.00%
Fair value of convertible senior note as percentage of principal amount |  | 113.75%
Convertible senior note carrying value of the liability component |  | $ 368,300
Convertible senior note assumed borrowing rate |  | 7.50%
Convertible senior note carrying value of the equity component |  | $ 149,200
Convertible senior notes |  | 7 years
Transaction cost related to issuance of convertible senior note |  | $ 14,700

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- Definition The percentage of excess of the price paid for the convertible note over the closing stock price on the closing date of the convertible note. + References No definition available. + Details
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- Definition The minimum percentage of the product of the common stock trading price multiplied by the conversion rate during the measurement period as compared to the principal note amount that triggers a conversion option on the notes, if it falls below this percentage. + References No definition available. + Details
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- Definition The rate of interest that was being paid on the original debt issue that is being converted in the 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 + Details
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- Definition The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031897-161870 + 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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- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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