Government Assistance - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023	Dec. 30, 2023	Dec. 30, 2023
Government Assistance [Line Items]
Food subsidies	$ 13,200,000	$ 10,900,000	$ 38,600,000	$ 33,700,000
COVID-19 Related Stimulus
Government Assistance [Line Items]
Revenue	200,000	1,400,000	300,000	3,000,000
Reimbursement of center operating expenses offsetting cost of services	16,900,000	36,900,000	55,900,000	145,200,000
COVID-19 Related Stimulus | Employee Retention Credit
Government Assistance [Line Items]
Reimbursements of cash tax refunds					$ 62,000,000
Reimbursements of interest income			500,000			$ 2,300,000
Reimbursement of cost of services	0	$ 0	23,400,000	$ 0
COVID-19 Related Stimulus | Prepaid Expenses and Other Current Assets
Government Assistance [Line Items]
Due from government assistance programs	1,300,000		1,300,000		1,000,000	1,000,000
COVID-19 Related Stimulus | Prepaid Expenses and Other Current Assets | Employee Retention Credit
Government Assistance [Line Items]
Due from government assistance programs	3,400,000		3,400,000
COVID-19 Related Stimulus | Other Current Liabilities
Government Assistance [Line Items]
Government support, deferred liability	7,200,000		7,200,000		18,100,000	18,100,000
COVID-19 Related Stimulus | Other Current Liabilities | Employee Retention Credit
Government Assistance [Line Items]
Government support, deferred liability	31,400,000		31,400,000		20,600,000	20,600,000
COVID-19 Related Stimulus | Other Long-term Liabilities | Employee Retention Credit
Government Assistance [Line Items]
Government support, deferred liability	$ 12,300,000		$ 12,300,000		$ 43,700,000	$ 43,700,000