Supplemental Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts
Beginning balance	$ 1.7	$ 1.0	$ 0.8
Bad debt expense	0.4	1.2	0.8
Recoveries	(0.3)	(0.2)	0.0
Write-offs and discounts	(0.3)	(0.3)	(0.6)
Ending balance	1.5	1.7	1.0
Interest paid	29.1	24.0	22.7
Income taxes paid	20.8	23.2	38.1
Capital spending in accounts payable and accrued liabilities	5.9	5.0	7.7
Deferred contingent business acquisition consideration	$ 0.0	$ 0.0	$ 8.6