Leases (Summary of Supplemental Cash Flow Information Related to Leases) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases		$ 8.0	$ 6.8	$ 6.3
Operating cash flows from finance leases		0.8	0.6	0.7
Financing cash flows from finance leases		2.7	2.2	2.1
ROU assets obtained in exchange for lease liabilities
Operating leases	[1]	15.8	3.9	7.3
Finance leases	[2]	$ 12.3	$ 0.0	$ 0.3

[1] The year ended December 31, 2023 included a decrease of $1.0 million in ROU assets due to a change in lease classification upon modification and an increase of $0.6 million resulting from modifications that did not involve obtaining a new ROU asset. The years ended December 31, 2022 and 2021 included increases in ROU assets of $1.0 million and $3.2 million, respectively, resulting from modifications that did not involve obtaining a new ROU asset. Modifications resulted primarily from changes in the terms of existing leases.

[2] The year ended December 31, 2023 included increases in ROU assets of $8.6 million due to the change in lease classification upon modification for an existing manufacturing facility within our Architectural Specialties segment which had a modified expected lease term of 13 years, in addition to an increase of $3.7 million for a lease modification that did not involve obtaining a new ROU asset.