Long-Term Borrowings - Additional Information (Details) - USD ($)				12 Months Ended
	Mar. 03, 2016	Feb. 25, 2015	May 27, 2014	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014	Aug. 06, 2013	Aug. 02, 2013	Aug. 01, 2012
Debt Instrument [Line Items]
Ownership interest in Suburban Energy Finance Corp (in hundredths)				100.00%
Loss on debt extinguishment				$ 292,000	$ 15,072,000	$ 11,589,000
Long-term borrowings				$ 1,238,172,000	1,241,107,000
Consolidated interest coverage ratio, minimum				2.5
Total consolidated leverage ratio, maximum				5.5
Notional Amount				$ 100,000,000
Consolidated fixed charge coverage ratio, minimum				1.75
Capitalized debt origination costs				$ 17,391,000	$ 18,458,000
Long-term debt maturities, 2017				0
Long-term debt maturities, 2018				0
Long-term debt maturities, 2019				0
Long-term debt maturities, 2020				0
Long-term debt maturities, 2021				446,180,000
Long-term debt maturities, 2021 and thereafter				775,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Standby letters of credit issued under the Revolving Credit Facility				$ 43,256,000
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]
Weighted average interest rate (in hundredths)				3.10%
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%
Amended Credit Agreement Due 2017 [Member]
Debt Instrument [Line Items]
Effective date				Jun. 25, 2013
Termination date				Jan. 05, 2017
Fixed interest rate (in hundredths)				1.63%
7.5% Senior Notes due October 1, 2018 [Member]
Debt Instrument [Line Items]
Date public offering completed				Aug. 01, 2012
Aggregate principal amount				$ 496,557,000
Stated interest rate (in hundredths)				7.50%
Maturity date				Oct. 01, 2018
Fair value of debt at acquisition date (in hundredths)									106.875%
Loss on debt extinguishment			$ 11,589,000
Redemption premium and related fees			31,633,000
Write-off unamortized debt origination costs			5,230,000
Write-off unamortized premium			$ (25,274,000)
7.375% Senior Notes due August 1, 2021 [Member]
Debt Instrument [Line Items]
Date public offering completed				Aug. 01, 2012
Aggregate principal amount				$ 503,443,000
Stated interest rate (in hundredths)				7.375%	7.375%
Maturity date				Aug. 01, 2021
Fair value of debt at acquisition date (in hundredths)									108.125%
Debt instrument repurchase amount							$ 23,863,000	$ 133,400,000
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
Long-term borrowings				$ 363,172,000	$ 366,107,000
5.5% Senior Notes due June 1, 2024 [Member]
Debt Instrument [Line Items]
Date public offering completed				May 27, 2014
Aggregate principal amount				$ 525,000,000
Stated interest rate (in hundredths)				5.50%	5.50%
Maturity date				Jun. 01, 2024
Percentage of principal amount at which debt was issued (in hundredths)				100.00%
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
5.75% Senior Notes due March 1, 2025 [Member]
Debt Instrument [Line Items]
Date public offering completed				Feb. 25, 2015
Aggregate principal amount				$ 250,000,000
Stated interest rate (in hundredths)				5.75%	5.75%
Maturity date				Mar. 01, 2025
Percentage of principal amount at which debt was issued (in hundredths)				100.00%
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
7.375% Senior Notes due March 15, 2020 [Member]
Debt Instrument [Line Items]
Loss on debt extinguishment		$ 15,072,000
Redemption premium and related fees		11,124,000
Write-off unamortized debt origination costs		2,855,000			2,855,000
Write-off unamortized discount		$ 1,093,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date				Mar. 03, 2021
Credit Facility, maximum amount	$ 500,000,000
Long-term borrowings				$ 100,000,000	100,000,000
Revolving Credit Facility [Member] | Amended Credit Agreement Due 2021 [Member]
Debt Instrument [Line Items]
Write-off unamortized debt origination costs				292,000
Revolving credit facility, term	5 years
Credit Facility, maximum amount	$ 500,000,000
Capitalized costs				$ 2,678,000
Revolving Credit Facility [Member] | Amended Credit Agreement Due 2017 [Member]
Debt Instrument [Line Items]
Credit Facility, maximum amount					$ 400,000,000