Long-Term Borrowings - Additional Information (Details) - USD ($)			12 Months Ended
	May 24, 2021	Mar. 05, 2020	Sep. 25, 2021	Sep. 26, 2020	Sep. 28, 2019	Feb. 25, 2015	May 27, 2014
Debt Instrument [Line Items]
Ownership interest in Suburban Energy Finance Corp (in hundredths)			100.00%
Long-term borrowings			$ 1,132,000,000	$ 1,219,600,000
Loss on debt extinguishment			$ 16,029,000	109,000	$ 0
Consolidated fixed charge coverage ratio, minimum			1.75
Capitalized costs				2,717,000
Long-term debt maturities, 2022			$ 0
Long-term debt maturities, 2023			0
Long-term debt maturities, 2024			0
Long-term debt maturities, 2025			132,000,000
Long-term debt maturities, 2026			0
Long-term debt maturities, thereafter			$ 1,000,000,000
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%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Consolidated interest coverage ratio, minimum			2.5
Total consolidated leverage ratio			5.75
Senior secured unconsolidated leverage ratio maximum			3.25
Amended Credit Agreement Due 2021 [Member]
Debt Instrument [Line Items]
Weighted average interest rate (in hundredths)			2.20%
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%
Senior Notes [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment	$ (16,029,000)
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term borrowings			$ 132,000,000	94,600,000
Maturity date		Mar. 05, 2025	Mar. 05, 2025
Write-off unamortized debt origination costs			$ 109,000
Standby letters of credit issued under the Revolving Credit Facility			$ 56,862,000
Standby letters of credit issued under the Revolving Credit Facility, expiration date			Apr. 30, 2022
Revolving Credit Facility [Member] | Third Amended and Restated Credit [Member]
Debt Instrument [Line Items]
Long-term borrowings			$ 132,000,000	94,600,000
Credit Facility, maximum amount		$ 500,000,000
Capitalized debt origination costs			$ 2,238,000	$ 3,164,000
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
5.0% Senior Notes due June 1, 2031 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)			5.00%	5.00%
Date public offering completed			May 24, 2021
Percentage of principal amount at which debt was issued (in hundredths)			100.00%
Maturity date			Jun. 01, 2031
Aggregate principal amount			$ 650,000,000
Debt instrument interest redemption percentage			35.00%
Redemption prices percentage			105.00%
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
Long-term borrowings				$ 525,000,000			$ 525,000,000
Percentage of principal amount at which debt was issued (in hundredths)			100.00%
Maturity date			Jun. 01, 2024
Redemption premium and related fees	6,217,000
Write-off unamortized debt origination costs	2,855,000
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
Long-term borrowings				250,000,000		$ 250,000,000
Percentage of principal amount at which debt was issued (in hundredths)			100.00%
Maturity date			Mar. 01, 2025
Redemption premium and related fees	5,241,000
Write-off unamortized debt origination costs	$ 1,716,000
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
Long-term borrowings			$ 350,000,000	$ 350,000,000
Percentage of principal amount at which debt was issued (in hundredths)			100.00%
Maturity date			Mar. 01, 2027
Aggregate principal amount			$ 350,000,000
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
Senior Notes [Member] | 7.375% Senior Notes due August 1, 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate (in hundredths)			7.375%
Senior Notes [Member] | 5.0% Senior Notes due June 1, 2031 [Member]
Debt Instrument [Line Items]
Long-term borrowings			$ 650,000,000
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