Computation of Earnings Per Share [Line Items]

No definition available.

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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- Definition

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

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- Definition

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

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- Definition

This element represents nonvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid). Basic and dilutive earnings per share are generally disclosed for such shares using the two-class method.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Earnings Per Share - Additional Information (Detail) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	May 24, 2016
Computation of Earnings Per Share [Line Items]
Participating securities outstanding	0	0	0	0
Stock options, outstanding	1,033,312		1,033,312		734,940
Stock options, weighted average exercise price	$ 26.99		$ 26.99		$ 20.80
Common stock excluded from calculation of diluted earnings per share	329,409	162,544	485,520	326,572
2.125% Convertible Senior Notes due 2021
Computation of Earnings Per Share [Line Items]
Notes, interest rate	2.125%		2.125%			2.125%
Notes, due date			Jun. 01, 2021
Option To Purchase Common Stock
Computation of Earnings Per Share [Line Items]
Stock options, outstanding	1,033,312	749,669	1,033,312	749,669
Stock options, weighted average exercise price	$ 26.99	$ 20.84	$ 26.99	$ 20.84
Restricted Stock Units (RSUs)
Computation of Earnings Per Share [Line Items]
Common stock excluded from calculation of diluted earnings per share			707,716	515,468