Long-Term Borrowings - Additional Information (Details) - USD ($)		3 Months Ended
	Mar. 05, 2020	Dec. 26, 2020	Sep. 26, 2020
Debt Instrument [Line Items]
Ownership interest in Suburban Energy Finance Corp (in hundredths)		100.00%
Long-term borrowings		$ 1,249,800,000	$ 1,219,600,000
Consolidated fixed charge coverage ratio, minimum		1.75
Long-term debt maturities, 2021		$ 0
Long-term debt maturities, 2022		0
Long-term debt maturities, 2023		0
Long-term debt maturities, 2024		649,800,000
Long-term debt maturities, 2025		250,000,000
Long-term debt maturities, 2025 and 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%
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)		2.50%
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]
Long-term borrowings		$ 124,800,000	94,600,000
Maturity date	Mar. 05, 2025	Mar. 05, 2025
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.
Standby letters of credit issued under the Revolving Credit Facility		$ 53,612,000
Standby letters of credit issued under the Revolving Credit Facility, expiration date		Nov. 01, 2021
Revolving Credit Facility [Member] | Third Amended and Restated Credit [Member]
Debt Instrument [Line Items]
Long-term borrowings		$ 124,800,000	$ 94,600,000
Credit Facility, maximum amount	$ 500,000,000
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
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
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] | 7.5% 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
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 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
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%