Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 10, 2017
Business Acquisition [Line Items]
Goodwill (tax deductible)	$ 72.8	$ 72.8
Farner-Bocken Company
Business Acquisition [Line Items]
Accounts receivable				$ 43.2
Inventories				35.5
Deposits and prepayments				10.2
Other receivables				0.4
Property and equipment				43.1
Goodwill (tax deductible)				36.8
Other intangible assets			$ 22.6	22.6
Less: Capital lease liability				(15.8)
Less: Accrued liabilities				(2.0)
Total consideration				$ 174.0