The indenture governing the 2020 Senior Notes, requires the Partnership's consolidated fixed charge coverage ratio, as defined, to exceed a minimum ratio to permit the Partnership to make cash distributions equal to available cash, as defined, as of the end of the immediately preceding quarter, if no event of default exists or would exist upon making such distributions.

No definition available.

Long-Term Borrowings - Additional Information (Details) - USD ($)	12 Months Ended
	Sep. 26, 2020	Mar. 05, 2020	Sep. 28, 2019
Debt Instrument [Line Items]
Ownership interest in Suburban Energy Finance Corp (in hundredths)	100.00%
Long-term borrowings	$ 1,219,600,000		$ 1,238,500,000
Consolidated fixed charge coverage ratio, minimum	1.75
Capitalized costs	$ 2,717,000
Long-term debt maturities, 2021	0
Long-term debt maturities, 2022	0
Long-term debt maturities, 2023	0
Long-term debt maturities, 2024	619,600,000
Long-term debt maturities, 2025	250,000,000
Long-term debt maturities, thereafter	$ 350,000,000
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Description of applicable interest rate on borrowings	Federal Funds Rate
Margin over basis rate (in hundredths)	0.50%
LIBOR [Member]
Debt Instrument [Line Items]
Description of applicable interest rate on borrowings	LIBOR
Margin over basis rate (in hundredths)	1.00%
Amended Credit Agreement Due 2021 [Member]
Debt Instrument [Line Items]
Consolidated interest coverage ratio, minimum	2.5
Total consolidated leverage ratio, maximum	5.75
Senior secured unconsolidated leverage ratio maximum	3.25
Weighted average interest rate (in hundredths)	2.80%
Amended Credit Agreement Due 2021 [Member] \| Federal Funds Rate [Member]
Debt Instrument [Line Items]
Description of applicable interest rate on borrowings	Federal Funds Rate
Margin over basis rate (in hundredths)	0.50%
Amended Credit Agreement Due 2021 [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Description of applicable interest rate on borrowings	LIBOR
Margin over basis rate (in hundredths)	1.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date	Mar. 05, 2025
Long-term borrowings	$ 94,600,000		113,500,000
Debt instrument maturity description	earlier of (a) the date that is ninety-one (91) days prior to maturity of the 2024 Senior Notes (unless the notes have been refinanced prior to such date) and (b) March 5, 2025.
Non cash charge recognized to write-off unamortized debt obligation costs	$ 109,000
Standby letters of credit issued under the Revolving Credit Facility	$ 63,088,000
Standby letters of credit issued under the Revolving Credit Facility, expiration date	Apr. 30, 2021
Write-off unamortized debt origination costs	$ 109,000
Revolving Credit Facility [Member] \| Amended Credit Agreement Due 2021 [Member]
Debt Instrument [Line Items]
Credit Facility, maximum amount		$ 500,000,000
Long-term borrowings	94,600,000	$ 183,900,000
Capitalized debt origination costs	$ 3,164,000		$ 1,550,000
5.5% Senior Notes due June 1, 2024 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.50%		5.50%
Maturity date	Jun. 01, 2024
5.75% Senior Notes due March 1, 2025 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.75%		5.75%
Maturity date	Mar. 01, 2025
5.875% Senior Notes due March 1, 2027 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.875%		5.875%
Maturity date	Mar. 01, 2027
Senior Notes [Member] \| 5.5% Senior Notes due June 1, 2024 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.50%
Date public offering completed	May 27, 2014
Aggregate principal amount	$ 525,000,000
Percentage of principal amount at which debt was issued (in hundredths)	100.00%
Maturity date	Jun. 01, 2024
Redemption start date	Jun. 01, 2019
Redemption description	The 2024 Senior Notes are redeemable, at the Partnership’s option, in whole or in part, at any time on or after June 1, 2019, in each case at the redemption prices described in the table below, together with any accrued and unpaid interest to the date of the redemption.
Percentage of the principal amount repurchase offer under change of control provision (in hundredths)	101.00%
Repurchase of debt due to decline in rating after consummation of change of control, period	90 days
Long-term borrowings	$ 525,000,000		$ 525,000,000
Senior Notes [Member] \| 7.5% Senior Notes due October 1, 2018 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	7.50%
Senior Notes [Member] \| 5.75% Senior Notes due March 1, 2025 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.75%
Date public offering completed	Feb. 25, 2015
Aggregate principal amount	$ 250,000,000
Percentage of principal amount at which debt was issued (in hundredths)	100.00%
Maturity date	Mar. 01, 2025
Redemption start date	Mar. 01, 2020
Redemption description	The 2025 Senior Notes are redeemable, at the Partnership’s option, in whole or in part, at any time on or after March 1, 2020, in each case at the redemption prices described in the table below, together with any accrued and unpaid interest to the date of the redemption.
Percentage of the principal amount repurchase offer under change of control provision (in hundredths)	101.00%
Repurchase of debt due to decline in rating after consummation of change of control, period	90 days
Long-term borrowings	$ 250,000,000		250,000,000
Senior Notes [Member] \| 7.375% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	7.375%
Senior Notes [Member] \| 5.875% Senior Notes due March 1, 2027 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	5.875%
Date public offering completed	Feb. 14, 2017
Aggregate principal amount	$ 350,000,000
Percentage of principal amount at which debt was issued (in hundredths)	100.00%
Maturity date	Mar. 01, 2027
Redemption start date	Mar. 01, 2022
Redemption description	The 2027 Senior Notes are redeemable, at the Partnership’s option, in whole or in part, at any time on or after March 1, 2022, in each case at the redemption prices described in the table below, together with any accrued and unpaid interest to the date of the redemption.
Percentage of the principal amount repurchase offer under change of control provision (in hundredths)	101.00%
Repurchase of debt due to decline in rating after consummation of change of control, period	90 days
Long-term borrowings	$ 350,000,000		$ 350,000,000
Senior Notes [Member] \| 7.375% Senior Notes due August 1, 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)	7.375%