Acquisitions - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014
Business Combination, Description [Abstract]
Acquisition related expenses included in pro-forma results	$ 16.8	$ 0.3
Goodwill impairment included in nonrecurring expenses	$ 0.4	$ 26.6

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

No definition available.

Name:	us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant