Partnership Organization - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012		Sep. 30, 2012
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage of limited partner interest	99.46%
Percentage of general partner interest	0.54%
Outstanding senior notes	$ 124,382	[1]	$ 124,357	[1]
Petro
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of Full-service residential and commercial home heating oil and propane customers served	417,000
Number of customers to whom home heating oil, gasoline and diesel fuel were sold	53,000
Number of customers to provide service	11,500
Common Stock
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of outstanding units	59,987		61,002
General Partner
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of outstanding units	326		326
Senior Notes
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership interest in Star Gas Finance Company	100.00%
Outstanding senior notes	$ 125,000
Interest on senior notes	8.875%
Maturity of senior notes	2017

[1] The 8.875% Senior Notes were originally issued in November 2010 in a private placement offering pursuant to Rule 144A and Regulation S under the Securities Act of 1933, and in February 2011, were exchanged for substantially identical public notes registered with the Securities and Exchange Commission. These public notes mature in December 2017 and accrue interest at an annual rate of 8.875% requiring semi-annual interest payments on June 1 and December 1 of each year. The discount on these notes was $0.6 million at December 31, 2012. Under the terms of the indenture, these notes permit restricted payments after passing certain financial tests. The Partnership can incur debt up to $100 million for acquisitions and can also pay restricted payments of $22.0 million without passing certain financial tests.