Impairment and Restructuring Charges (Details Textual) $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($) Positions	Dec. 31, 2016 USD ($) Positions	Dec. 31, 2015 USD ($)
Restructuring and Related Cost [Line Items]
Exit costs		$ 0.1		$ 0.1		$ 0.1	$ 0.6
Tangible Asset Impairment Charges				0.0			0.0
Severance Costs		0.2		0.7		0.4	1.9
Restructuring, Settlement and Impairment Provisions	$ 0.3	0.3	$ 0.8	0.8	$ 0.5	$ 2.5	$ 2.5
Restructuring accrual		7.5						$ 10.1
WorkforceReduction [Member]
Restructuring and Related Cost [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Positions						50	175
Severance Costs		0.7		1.7		$ 1.5	$ 7.7
Mobile Industries [Member]
Restructuring and Related Cost [Line Items]
Exit costs		0.1		0.1		0.1	0.1
Tangible Asset Impairment Charges				0.0			0.0
Severance Costs		0.0		0.6		0.2	1.8
Restructuring, Settlement and Impairment Provisions		0.1		0.7		0.3	1.9
Mobile Industries [Member] | WorkforceReduction [Member]
Restructuring and Related Cost [Line Items]
Severance Costs							2.9
Process Industries [Member]
Restructuring and Related Cost [Line Items]
Exit costs		0.0		0.0		0.0	0.0
Tangible Asset Impairment Charges				0.0			0.0
Severance Costs		0.1		0.1		0.1	0.1
Restructuring, Settlement and Impairment Provisions		0.1		0.1		0.1	0.1
Process Industries [Member] | WorkforceReduction [Member]
Restructuring and Related Cost [Line Items]
Severance Costs							4.8
Corporate Segment [Member]
Restructuring and Related Cost [Line Items]
Exit costs		0.0		0.0		0.0	0.5
Tangible Asset Impairment Charges				0.0			0.0
Severance Costs		0.1		0.0		0.1	0.0
Restructuring, Settlement and Impairment Provisions		0.1		0.0		0.1	0.5
Pulaski [Member]
Restructuring and Related Cost [Line Items]
Restructuring, Settlement and Impairment Provisions						$ 8.1
Pulaski [Member] | WorkforceReduction [Member]
Restructuring and Related Cost [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Positions						120
Severance Costs		$ 0.2				$ 1.3
Benoni [Member]
Restructuring and Related Cost [Line Items]
Tangible Asset Impairment Charges							0.5
Benoni [Member] | WorkforceReduction [Member]
Restructuring and Related Cost [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | Positions						85
Severance Costs							0.8
Altavista Bearing Plant [Member] [Member]
Restructuring and Related Cost [Line Items]
Tangible Asset Impairment Charges				0.7			3.1
Severance Costs				$ 0.2			$ 1.7
Restructuring, Settlement and Impairment Provisions						$ 11.5