Summary of Significant Accounting Policies, Narrative (Details) $ in Millions		3 Months Ended								12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounting policies additional disclosures
Number of operating segments | segment										1
Advertising costs										$ 0.7	$ 0.4	$ 1.2
Research and development costs										10.0	10.2	9.5
Lower of cost or market inventory write-down						$ 0.0	$ 0.0	$ 0.0	$ 4.9	0.0	4.9	2.6
Excess of current cost over the stated LIFO value of inventory		$ 24.3				(8.5)				24.3	(8.5)
Non-cash impairment charges										19.2	2.8	0.1
Impairment of the carrying value of goodwill		18.4				0.0				18.4	0.0	0.0
Undiscounted workers' compensation liabilities										$ 24.8	$ 26.8
Discount rate used in estimating liabilities for worker compensation claims										2.25%	2.00%
Accrued employee healthcare benefits		3.5				3.6				$ 3.5	$ 3.6
Cumulative effect adjustment to Net sales		353.1	$ 332.8	$ 356.3	$ 355.3	331.9	$ 320.6	$ 334.9	$ 343.2	1,397.5	1,330.6	$ 1,391.9
Reduction in inventories		(207.9)				(201.6)				(207.9)	(201.6)
Reduction in deferred tax assets, net		(67.7)				(156.4)				(67.7)	(156.4)
Increase in retained earnings		$ 85.5				$ 75.2				$ 85.5	$ 75.2
Minimum
Accounting policies additional disclosures
Period over which accounts receivable is due, days										30 days
Number of days in maturity for debt investment securities to be classified as short-term investments										90 days
Maximum
Accounting policies additional disclosures
Period over which accounts receivable is due, days										90 days
Number of days to maturity for debt investment securities to be classified as cash and cash equivalents										90 days
Cumulative effect adjustment | Scenario, Forecast | Cumulative effect adjustment of ASU 2014-09
Accounting policies additional disclosures
Cumulative effect adjustment to Net sales	$ 55.6
Contract asset	55.6
Reduction in inventories	42.2
Reduction in deferred tax assets, net	3.3
Increase in retained earnings	$ 10.1