Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended				6 Months Ended
	Dec. 28, 2024	Sep. 28, 2024	Dec. 30, 2023	Sep. 30, 2023	Dec. 28, 2024	Dec. 30, 2023
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ 895,900,000	$ 957,300,000	$ 1,310,800,000	$ 1,355,800,000	$ 957,300,000	$ 1,355,800,000
Other comprehensive gain (loss), net	(1,400,000)	2,300,000	4,000,000.0	1,100,000	900,000	5,100,000
Balance at the end of the period	872,300,000	895,900,000	1,277,800,000	1,310,800,000	872,300,000	1,277,800,000
Unrealized loss on available-for-sale securities is presented net of tax	0		1,000,000		0	1,400,000
Total
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	11,600,000	9,300,000	5,200,000	4,100,000	9,300,000	4,100,000
Other comprehensive gain (loss), net	(1,400,000)	2,300,000	4,000,000.0	1,100,000
Balance at the end of the period	10,200,000	11,600,000	9,200,000	5,200,000	10,200,000	9,200,000
Foreign Currency Translation Adjustments, Net of Tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	9,800,000	9,800,000	10,200,000	10,400,000	9,800,000	10,400,000
Other comprehensive gain (loss), net	(300,000)	0	200,000	(200,000)
Balance at the end of the period	9,500,000	9,800,000	10,400,000	10,200,000	9,500,000	10,400,000
Defined Benefit Obligations, Net of Tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	700,000	700,000	(400,000)	(400,000)	700,000	(400,000)
Other comprehensive gain (loss), net	0	0	0	0
Balance at the end of the period	700,000	700,000	(400,000)	(400,000)	700,000	(400,000)
Unrealized Gain (Loss) on Available-for-sale Securities, Net of Tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	1,100,000	(1,200,000)	(4,600,000)	(5,900,000)	(1,200,000)	(5,900,000)
Other comprehensive gain (loss), net	(1,100,000)		3,800,000	1,300,000
Balance at the end of the period	$ 0	$ 1,100,000	$ (800,000)	$ (4,600,000)	$ 0	$ (800,000)