Other Commitments and Contingencies - Additional Information (Detail) $ in Thousands, gal in Millions	3 Months Ended
	Sep. 30, 2016 USD ($) gal	Dec. 31, 2015 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Number of years to purchase propane under contract	6 years
Estimated current annual commitment | gal	6.5
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	0.65
Maximum authorized liability under such guarantees and letters of credit	$ 65,000
Aggregate guaranteed amount	53,900
Draws on letters of credit	8,400
Liability related to unrecognized income tax benefits	$ 50
Liability related to contingencies for taxes other than income		$ 310