Goodwill And Intangible Assets (Summary Of Intangible Assets) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years 9 months 18 days
Intangible Assets, Gross (Excluding Goodwill)	$ 900.2	$ 908.2
Finite-Lived Intangible Assets, Accumulated Amortization	408.9	389.1
Intangible assets, net	491.3	519.1	$ 503.7
Remainder of 2021	22.2
2022	42.8
2023	42.8
2024	41.8
2025 and after	$ 270.5
Intellectual Property Rights
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years 2 months 12 days
Intangible Assets, Gross (Excluding Goodwill)	$ 133.0	133.2
Finite-Lived Intangible Assets, Accumulated Amortization	54.0	53.4
Intangible assets, net	$ 79.0	79.8
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	18 years 3 months 18 days
Intangible Assets, Gross (Excluding Goodwill)	$ 617.1	623.7
Finite-Lived Intangible Assets, Accumulated Amortization	257.5	241.9
Intangible assets, net	$ 359.6	381.8
Drawings
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	40 years
Intangible Assets, Gross (Excluding Goodwill)	$ 11.1	11.1
Finite-Lived Intangible Assets, Accumulated Amortization	10.6	10.5
Intangible assets, net	$ 0.5	0.6
Other Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	11 years 8 months 12 days
Intangible Assets, Gross (Excluding Goodwill)	$ 139.0	140.2
Finite-Lived Intangible Assets, Accumulated Amortization	86.8	83.3
Intangible assets, net	$ 52.2	$ 56.9