Share-Based Compensation - Schedule of Stock Options Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of options
Outstanding at the beginning of the year (in shares)	0	0	17
Exercised during the year (in shares)	0	0	(17)
Forfeited or expired during the year (in shares)	0	0	0
Outstanding and exercisable at year end (in shares)	0	0	0
Weighted- average exercise price
Outstanding at the beginning of the year (in USD per share)			$ 31.64
Exercised during the year (in USD per share)	$ 0.00	$ 0.00	31.64
Forfeited or expired during the year (in USD per share)	$ 0.00	$ 0.00	$ 0.00
Outstanding and exercisable	$ 0	$ 0	$ 0
Exercised	$ 0	$ 0	$ 554

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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- Definition

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

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Number of share options (or share units) exercised during the current period.

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