Basis of Reporting for Consolidated Financial Statements - Additional Information (Detail)	12 Months Ended
Dec. 31, 2014 Acquisition
Adjusted Earnings Before Interest Taxes Depreciation And Amortization And Other Non Cash Items [Abstract]
Number of acquisitions	4us-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