Share-Based Compensation - Additional Information (Detail) $ in Thousands	6 Months Ended
Jun. 30, 2018 USD ($)
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Unrecognized compensation cost related to unvested share-based equity awards	$ 134,342
Weighted average period of recognition of unvested share-based equity awards	1 year 8 months
Unrecognized compensation cost related to unvested share-based equity awards, stock options	$ 37,441
Unrecognized compensation cost related to unvested share-based equity awards, restricted stock	$ 96,901

No definition available.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

+ Details

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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