Goodwill and Other Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Millions	Dec. 27, 2020	Dec. 29, 2019
Acquired finite-lived intangible assets:
Gross Value	$ 150.0	$ 139.7
Accumulated Amortization	(113.9)	(107.1)
Total	36.1	32.6
Total intangible assets, Gross Value	156.9	146.6
Total intangible assets, Net Value	43.0	39.5
Trade names
Acquired finite-lived intangible assets:
Indefinite-lived trade names	6.9	6.9
Customer relationships
Acquired finite-lived intangible assets:
Gross Value	75.3	72.3
Accumulated Amortization	(55.7)	(53.3)
Total	19.6	19.0
Contracts and backlog
Acquired finite-lived intangible assets:
Gross Value	33.4	32.0
Accumulated Amortization	(31.0)	(28.4)
Total	2.4	3.6
Developed technology and technical know-how
Acquired finite-lived intangible assets:
Gross Value	29.9	25.0
Accumulated Amortization	(25.3)	(23.8)
Total	4.6	1.2
Trade names
Acquired finite-lived intangible assets:
Gross Value	2.0	1.9
Accumulated Amortization	(1.9)	(1.6)
Total	0.1	0.3
In-process research and development
Acquired finite-lived intangible assets:
Gross Value	9.4	8.5
Accumulated Amortization	0.0	0.0
Total	$ 9.4	$ 8.5