Other Commitments and Contingencies - Additional Information (Detail) $ in Thousands, gal in Millions		1 Months Ended		12 Months Ended
	Feb. 02, 2017 USD ($)	Feb. 28, 2017 USD ($)	May 31, 2013	Dec. 31, 2016 USD ($) gal	Dec. 31, 2015 USD ($)
Subsequent Event [Line Items]
Intercompany Agreements, Description				3
Number Of Years To Purchase Propane Under Contract			6 years
Annual Estimate Of Volume Of Propane To Be Purchased | gal				3.4
Total liabilities to tangible net worth minimum times				3.75
Fixed charge coverage ratio minimum times				1.5
Time to cure ratio				30 days
Funds from operations interest coverage ratio minimum times				2
Total debt to capital maximum				65
Number Of Years to Collect Benefits				20 years
Total purchase obligations for 2017				$ 90,000
Total purchase obligations for 2018 - 2019				94,600
Total purchase obligations for 2020 - 2021				39,500
Total purchase obligations thereafter				82,200
Maximum authorized liability under such guarantees and letters of credit				65,000
Aggregate guaranteed amount				57,200
Amount of letter of credit to our current primary insurance company				8,500
Liability for Uncertainty in Income Taxes, Noncurrent				$ 50
Accruals related to additional sales taxes and gross receipts taxes					$ 310
Subsequent Event [Member]
Subsequent Event [Line Items]
Estimated Capital Cost	$ 59,800
Number Of Years In Project	5 years
Maximum authorized liability under such guarantees and letters of credit		$ 85,000