Acquisitions - Additional Information (Detail)	3 Months Ended
Mar. 31, 2015 Entity
Business Acquisition [Line Items]
Number of other tuck-in acquisitions	2us-gaap_NumberOfBusinessesAcquired

The number of businesses acquired by the entity during the period.

No definition available.

Name:	us-gaap_NumberOfBusinessesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration