The cost of the purchased capped calls recorded to shareholders' equity that will not be re-measured.

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Ceiling on the conversion price of the convertible debt.

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Notes Measurement Period

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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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Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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Expiration, mandatory redemption, or due date, in CCYY-MM-DD format, of the financial instrument issued in exchange for the original debt being converted in a noncash or part noncash transaction.

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Dividend or interest rate associated with the financial instrument issued in exchange for the original debt being converted in a noncash or part noncash transaction. Noncash are transactions that affect recognized assets or liabilities but that do not result in cash receipts or cash payments. Part noncash refers to that portion of the transaction not resulting in cash receipts or cash payments.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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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.

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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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Price of the entity's common stock which would be required to be attained for the conversion feature embedded in the debt instrument to become effective.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instruments must exceed threshold percentage for a specified number of trading days to trigger conversion feature, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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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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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Amount of debt issuance costs (for example, but not limited to, legal, accounting, broker, and regulatory fees).

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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Price of a single share of a number of saleable stocks of a company.

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Convertible Senior Notes - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 28, 2014	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Convertible notes issued		$ 284,295,000	$ 281,627,000
Initial strike price of common stock (in dollars per share)		$ 65.10
Conversion of notes, cap price (in dollars per share)		$ 78.61
Cost of purchased capped calls		$ 25,100,000
Closing price of common stock (in dollars per share)		$ 33.36
Convertible senior notes
Debt Instrument [Line Items]
Convertible notes issued	$ 345,000,000
Convertible notes fixed rate (as percent)	1.25%
Convertible notes, maturity date		Feb. 01, 2021
Convertible debt, conversion rate	0.0153616
Conversion price per share of common stock (in dollars per share)	$ 65.10
Debt converted into number of common shares (in shares)	5,300,000
Convertible debt maturity date		Aug. 01, 2020
Convertible debt, interest rate		5.00%
Convertible debt, fair value of liability		$ 270,000,000
Convertible debt discount, recorded in additional paid in capital	$ 75,000,000
Debt instrument transaction costs		7,200,000
Convertible senior notes \| Scenario One
Debt Instrument [Line Items]
Debt instrument trading days	20 days
Consecutive trading days	30 days
Percentage of conversion price	130.00%
Convertible senior notes \| Scenario Two
Debt Instrument [Line Items]
Notes Measurement Period	5 days
Consecutive trading days	5 days
Percentage of conversion price	98.00%
Equity component
Debt Instrument [Line Items]
Debt instrument transaction costs		$ 2,000,000	$ 2,000,000