Accounting Standards - Additional Information (Detail) - Accounting Standards Update 2016-09 $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative-effect adjustments to retained earnings (deficit) and reduced deferred tax liability	$ 101.1
Recognition of an excess tax deficiency in provision for income taxes rather than paid-in capital	$ 2.1

Amount of the effect of a change in accounting principle on net income.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

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