Partnership's Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Sep. 30, 2012
Debt [Line Items]
8.875% Senior Notes, Carrying Amount	$ 124,382	[1]	$ 124,357	[1]
Revolving Credit Facility Borrowings, Carrying Amount	36,703	[2]
Total debt, Carrying Amount	161,085		124,357
Total long-term portion of debt, Carrying Amount	124,382		124,357
8.875% Senior Notes, Estimated Fair Value	126,875	[1],[3]	126,563	[1],[3]
Revolving Credit Facility Borrowings, Estimated Fair Value	36,703	[2],[3]
Total debt, Estimated Fair Value	163,578	[3]	126,563	[3]
Total long-term portion of debt, Estimated Fair Value	$ 126,875	[3]	$ 126,563	[3]

[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.

[2] In June 2011, the Partnership entered into an amended and restated asset based revolving credit facility agreement with a bank syndication comprised of fifteen banks. The amended and restated revolving credit facility expires in June 2016. In November 2011, the Partnership exercised the provision under this agreement to expand the facility by an additional $50 million. Under this agreement, the Partnership may borrow up to $250 million ($350 million during the heating season from December to April each year) for working capital purposes (subject to certain borrowing base limitations and coverage ratios) and may issue up to $100 million in letters of credit. The Partnership can increase the facility size by $100 million without the consent of the bank group. The bank group is not obligated to fund the $100 million increase. If the bank group elects not to fund the increase, the Partnership can add additional lenders to the group, with the consent of the agent (as appointed in the revolving credit facility agreement), which shall not be unreasonably withheld.

[3] The Partnership's fair value estimates of long-term debt are made at a specific point in time, based on relevant market information, open market quotations and information about the financial instrument. These estimates are subjective in nature and involve uncertainties and matters of significant judgment. Changes in assumptions could significantly affect the estimates.