Acquisitions - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	5 Months Ended
	Mar. 31, 2018	Feb. 28, 2019	Oct. 31, 2018	Mar. 01, 2018
Mountain Valley Acquisition
Business Acquisition [Line Items]
Consideration transferred		$ 80.0
Post-closing Capital Adjustment		0.4
Cash paid to sellers		62.5
Cash paid on behalf of sellers for sellers’ transaction expenses		1.8
Purchase price		$ 80.0	$ 80.4
Crystal Rock Acquisition
Business Acquisition [Line Items]
Consideration transferred	$ 37.7
Cash paid to sellers	20.7
Cash paid on behalf of sellers for sellers’ transaction expenses	0.8
Liabilities incurred	16.2
Purchase price	$ 21.5			$ 21.5