Partnership's Debt (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013
Debt Instrument [Line Items]
Revolving credit facility expiry	Dec. 31, 2016
Maximum issuable letter of credit	$ 100
8.875% Senior Notes
Debt Instrument [Line Items]
Senior notes issuance date	Nov. 01, 2010
Interest accrued by public notes for each year	8.875%
Discount on notes	0.5
Maximum debt allowed for acquisitions	100
Restricted payments without passing certain financial tests	22
Maturity of public notes due	Dec. 01, 2017
Interest payment frequency	Semi-annual interest payments on June 1 and December 1 of each year
First Amendment
Debt Instrument [Line Items]
Non Seasonal maximum borrowing capacity under revolving credit facility	250
Maximum borrowing capacity (heating season December to April) under revolving credit facility	$ 350