Goodwill and Other Intangible Assets - Gross carrying amount and accumulated amortization of the company's intangible assets other than goodwill (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	$ 166.1	$ 171.3
Finite-lived intangible assets, amortization amount	(48.0)	(49.2)
Intangible assets, book value	118.1	122.1
Customer Relationships
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	10.1	10.7
Finite-lived intangible assets, amortization amount	(8.4)	(8.7)
Finite-lived intangible assets, book value	1.7	2.0
Patents
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	29.8	30.6
Finite-lived intangible assets, amortization amount	(29.0)	(29.7)
Finite-lived intangible assets, book value	0.8	0.9
Engineering Drawings
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	10.5	10.8
Finite-lived intangible assets, amortization amount	(10.5)	(10.7)
Finite-lived intangible assets, book value	0.0	0.1
Distribution Network
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	19.0	19.5
Finite-lived intangible assets, amortization amount	(0.1)	(0.1)
Finite-lived intangible assets, book value	18.9	19.4
Trademarks and Tradenames
Intangible asset balances by major asset class
Indefinite-lived intangible assets, book value	$ 96.7	$ 99.7