Goodwill and Other Intangible Assets - Gross carrying amount and accumulated amortization of the company's intangible assets other than goodwill (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	$ 152.9	$ 153.5
Finite-lived intangible assets, amortization amount	(37.0)	(37.2)
Intangible assets, book value	115.9	116.3
Indefinite-lived Intangible Assets
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	113.7	114.0
Intangible assets, book value	113.7	114.0
Indefinite-lived Intangible Assets | Distribution Network
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	18.6	18.7
Finite-lived intangible assets, book value	18.6	18.7
Indefinite-lived Intangible Assets | Trademarks and Tradenames
Intangible asset balances by major asset class
Indefinite-lived intangible assets, book value	95.1	95.3
Finite-Lived Intangible Assets
Intangible asset balances by major asset class
Intangible assets, gross (excluding goodwill)	39.2	39.5
Finite-lived intangible assets, amortization amount	(37.0)	(37.2)
Intangible assets, book value	2.2	2.3
Finite-Lived Intangible Assets | Customer Relationships
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	9.7	10.0
Finite-lived intangible assets, amortization amount	(8.2)	(8.5)
Finite-lived intangible assets, book value	1.5	1.5
Finite-Lived Intangible Assets | Patents
Intangible asset balances by major asset class
Finite-lived intangible assets, carrying amount	29.5	29.5
Finite-lived intangible assets, amortization amount	(28.8)	(28.7)
Finite-lived intangible assets, book value	$ 0.7	$ 0.8