Long-Term Debt and Bank Facility Borrowings - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jul. 31, 2011
Debt Instrument [Line Items]
Alternate revolving credit facility expiry	Dec. 31, 2016
Letters of credit issued	$ 46.5	$ 44.7
Availability in compliance with the fixed charge coverage ratio	148.0	164.3
Available sale of offering of common units under shelf registration			250
Second Amendment
Debt Instrument [Line Items]
Non Seasonal maximum borrowing capacity under revolving credit facility	300
Maximum borrowing capacity (heating season December to April) under revolving credit facility	450
Alternate revolving credit facility expiry	Jan. 14, 2019
Revolving credit facility expiry	Jun. 01, 2017
Additional revolving credit	100
Facility size that can be increased without consulting bank group	100
Description of variable rate	The interest rate on the second amended and restated credit facility is LIBOR plus (i) 1.75% (if Availability, as defined in the agreement is greater than or equal to $150 million), or (ii) 2.00% (if Availability is greater than $75 million but less than $150 million), or (iii) 2.25% (if Availability is less than or equal to $75 million). The Commitment Fee on the unused portion of the facility is 0.30% per annum.
Condition one, additional interest rate based on LIBOR	1.75%
Condition two, additional interest rate based on LIBOR	2.00%
Condition three, additional interest rate based on LIBOR	2.25%
Minimum availability, condition one	150
Maximum availability, condition two	150
Minimum availability, condition two	75
Maximum availability, condition three	75
Commitment fee on the unused portion of the facility	0.30%
Availability percentage to maximum facility size	12.50%
Minimum fixed charge coverage ratio	1.1
Availability required to make acquisition	40
Availability required to pay distributions	45
Percentage of the maximum facility size on a historical proforma and forward-looking basis	15.00%
Minimum fixed charge coverage ratio for distributions to unit holders or to repurchase common units	1.15
Line of credit facility description	All outstanding amounts owed under the second amended and restated credit facility become due and payable on the facility termination date of June 1, 2017. If the Partnership has repaid, prepaid or otherwise defeased at least $100 million of our 8.875% Senior Notes and Availability is equal to or greater than the aggregate amount required to repay the remaining outstanding 8.875% Senior Notes ("Payoff Amount"), then the facility termination date is January 14, 2019.
Second Amendment | Prior to the January 2014 agreement
Debt Instrument [Line Items]
Percentage of the maximum facility size on a historical proforma and forward-looking basis	17.50%
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility outstanding	$ 100.3	$ 0
8.875% Senior Notes
Debt Instrument [Line Items]
Interest accrued by public notes for each year	8.875%
8.875% Senior Notes | Second Amendment
Debt Instrument [Line Items]
Interest accrued by public notes for each year	8.875%