Special Charges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restructuring Cost and Reserve [Line Items]
Special charges	$ 0.2	$ 0.3	$ 0.2	$ 1.9
Write offs of cumulative translation adjustments			14.4
Balance beginning of period			20.5
Charged to expense			4.0
Paid or otherwise settled			(3.8)
Balance end of period	20.7		20.7
NATG [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Additional charges			1.0
NATG [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Additional charges			2.0
NATG [Member] | Continuing Operations [Member]
Restructuring Cost and Reserve [Line Items]
Special charges	0.2		4.3
Special charges related to future lease cash flows	0.2		3.7
Special charges related to ongoing restitution proceedings			0.6
NATG [Member] | Discontinued Operations [Member]
Restructuring Cost and Reserve [Line Items]
Special charges	3.5		4.3
Special charges related to future lease cash flows	3.2		3.7
Special charges related to ongoing restitution proceedings	0.3		0.6
SARL Business [Member]
Restructuring Cost and Reserve [Line Items]
Vendor guarantees	0.6		0.6
SARL Business [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Additional charges			1.0
SARL Business [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Additional charges			2.0
SARL Business [Member] | Discontinued Operations [Member]
Restructuring Cost and Reserve [Line Items]
Additional charges	0.9
Write offs of cumulative translation adjustments			14.4
Net asset write-offs			8.2
Legal, professional and other costs	0.3		1.0
Severance and other personnel costs	0.3		0.3
Accelerated depreciation charges	0.3		0.3
Require use of cash	1.3		1.3
Charged to expense			24.2
Severance and Other Costs [Member] | ETG [Member]
Restructuring Cost and Reserve [Line Items]
Balance beginning of period			0.0
Charged to expense			0.3
Paid or otherwise settled			(0.2)
Balance end of period	0.1		0.1
Lease Liabilities and Other Costs [Member] | ETG [Member]
Restructuring Cost and Reserve [Line Items]
Balance beginning of period			1.2
Charged to expense			0.0
Paid or otherwise settled			0.0
Balance end of period	1.2		1.2
Lease Liabilities and Other Exit Costs [Member] | NATG [Member]
Restructuring Cost and Reserve [Line Items]
Balance beginning of period			19.3
Charged to expense			3.7
Paid or otherwise settled			(3.6)
Balance end of period	$ 19.4		$ 19.4