Other Commitments and Contingencies - Additional Information (Detail) gal in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) dekatherm / d gal	Dec. 31, 2014 USD ($) dekatherm / d
Other Contingencies And Commitments [Line Items]
Number of years to purchase propane under contract	6 years
Annual Estimate Of Volume Of Propane To Be Purchased | 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
Document Period End Date	Jun. 30, 2015
Maximum authorized liability under such guarantees and letters of credit	$ 50,000,000
Aggregate guaranteed amount	32,000,000
Draws on letters of credit	0
Liability for Uncertain Tax Positions, Noncurrent	100,000	$ 100,000
Unrecognized Tax Benefits	$ 525,000	$ 724,000
Purchase Commitment Minimum Volume | dekatherm / d	9,982
Purchase Commitment Maximum Volume | dekatherm / d		13,423
September 12, 2013 [Member]
Other Contingencies And Commitments [Line Items]
Amount of letter of credit to our current primary insurance company	$ 1,000,000
December 2, 2013 [Member]
Other Contingencies And Commitments [Line Items]
Amount of letter of credit to our current primary insurance company	1,200,000
June 1, 2014 [Member]
Other Contingencies And Commitments [Line Items]
Amount of letter of credit to our current primary insurance company	40,000
TETLP Letter of Credit [Member] | Texas Eastern Transmission, LP [Member]
Other Contingencies And Commitments [Line Items]
Amount of letter of credit to our current primary insurance company	$ 2,300,000