Accumulated Other Comprehensive Loss - Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ 271.4		$ 233.9		$ 495.6	$ 438.9
Total before tax	17.2		29.9		30.0	37.0
Income taxes	(5.1)		0.2		(5.4)	(1.9)
Net earnings	12.1		30.1		24.6	35.1
Total reclassifications for the period	0.1	$ 0.4	0.2	$ (0.1)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	0.0		0.0		0.3	(0.2)
Gains and Losses on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	0.7	1.0	0.7	0.4
Gains and Losses on Cash Flow Hedges | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	0.7		0.7		1.7	1.1
Total before tax	0.7		0.7		1.7	1.1
Income taxes	(0.1)		(0.3)		(0.4)	(0.5)
Net earnings	0.6		0.4		1.3	0.6
Pension & Postretirement
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	(0.6)	$ (0.6)	(0.5)	$ (0.5)
Pension & Postretirement | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(0.6)		(0.5)		(1.2)	(1.0)
Income taxes	0.0		0.1		0.2	0.2
Total reclassifications for the period	(0.6)		(0.4)		(1.0)	(0.8)
Foreign currency exchange contracts | Gains and Losses on Cash Flow Hedges | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	(0.1)		0.5		0.4	0.7
Commodity contracts | Gains and Losses on Cash Flow Hedges | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ 0.8		$ 0.2		$ 1.3	$ 0.4