Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax (expense) benefit	$ (144)	$ 2,863	$ (15,700)
Earnings from discontinued operations, net of income taxes	$ 370	$ 2,690	$ 17,032
Net earnings from discontinued operations, basic (in usd per share)	$ 0.02	$ 0.10	$ 0.60
Net earnings from discontinued operations, diluted (in usd per share)	$ 0.02	$ 0.10	$ 0.59
Qdoba
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Company restaurant sales	$ 0	$ 0	$ 192,620
Franchise revenues	0	0	9,337
Company restaurant costs (excluding depreciation and amortization)	0	0	(166,122)
Franchise costs (excluding depreciation and amortization)	0	0	(2,338)
Selling, general and administrative expenses	244	174	(19,286)
Depreciation and amortization	0	0	(5,012)
Impairment and other charges, net	270	(262)	(2,305)
Interest expense, net	0	0	(4,787)
Operating earnings (loss) from discontinued operations before income taxes	514	(88)	2,107
(Loss) gain on Qdoba Sale	0	(85)	30,717
Earnings (loss) from discontinued operations before income taxes	514	(173)	32,824
Income tax (expense) benefit	(144)	2,863	(15,726)
Earnings from discontinued operations, net of income taxes	$ 370	$ 2,690	$ 17,098
Net earnings from discontinued operations, basic (in usd per share)	$ 0.02	$ 0.10	$ 0.60
Net earnings from discontinued operations, diluted (in usd per share)	$ 0.02	$ 0.10	$ 0.59