Acquisitions and Dispositions - Additional Information (Detail)	3 Months Ended
Mar. 31, 2019 Acquisition Disposition	Mar. 31, 2018 Acquisition Disposition
Business Combinations [Abstract]
Number of acquisitions \| Acquisition	0	0
Number of dispositions \| Disposition	0	0

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