Recent Accounting Pronouncements - Additional Information (Detail)	Dec. 31, 2014 USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Current deferred income tax asset	$ 0
Noncurrent deferred income tax liability	83,100,000
Previously Recognized
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Current deferred income tax asset	4,600,000
Noncurrent deferred income tax liability	$ 87,700,000