Retirement Benefit Plans Part 2 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Plans with accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	$ 2.3	$ 2.2
Fair value of plan assets	0.0	0.0
Plans with projected benefit obligation in excess of plan assets
Projected benefit obligation	2.3	2.2
Fair value of plan assets	0.0	0.0
Changes in Accumulated Other Comprehensive Loss:
Total recognized in other comprehensive (loss) income	0.5	(1.7)	$ (5.9)
Pension Plan
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	17.2
Fair value of plan assets at end of year	15.0	$ 17.2
Amounts that will be amortized from Accumulated Other Comprehensive Loss in next fiscal year
Net actuarial loss	$ 0.1
Postretirement Medical Benefits
Weighted-average assumptions used to determine benefit obligation
Discount rate	3.06%	3.95%
Rate of compensation increase	0.00%	0.00%
Weighted-average assumptions used to determine net periodic benefit costs
Discount rate	3.95%	3.26%	3.58%
Expected long-term rate of return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	0.00%	0.00%	0.00%
Assumed healthcare cost trend rates
Healthcare cost trend rate assumption for the next year	6.22%	6.38%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2032	2032
Effect of one-percentage-point change in assumed healthcare cost trends
Effect of one-percentage-point decrease on total of service and interest cost components	$ 0.0
Effect of one-percentage-point increase on total of service and interest cost components	0.0
Effect of one-percentage-point decrease on postretirement benefit obligation	(0.5)
Effect of one-percentage-point increase on postretirement benefit obligation	0.6
Change in benefit obligation:
Benefit obligation at beginning of year	8.6	$ 9.6
Service cost	0.0	0.1	$ 0.0
Interest cost	0.3	0.3	0.4
Plan amendments	0.0	0.0
Actuarial loss (gain)	(0.1)	(0.5)
Foreign exchange	0.0	0.0
Benefits paid	(1.0)	(0.9)
Settlement	0.0	0.0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0.0	0.0
Benefit obligation at end of year	7.8	8.6	9.6
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contributions	1.0	0.9
Foreign exchange	0.0	0.0
Benefits paid	(1.0)	(0.9)
Settlement	0.0	0.0
Fair value of plan assets at end of year	0.0	0.0	0.0
Funded status at end of year	(7.8)	(8.6)
Amounts recognized in the Consolidated Balance Sheets consist of:
Noncurrent Other Assets	0.0	0.0
Current Liabilities	(0.7)	(0.8)
Long-Term Liabilities	(7.1)	(7.8)
Net accrued (liability) asset	(7.8)	(8.6)
Amounts recognized in Accumulated Other Comprehensive Loss consist of:
Prior service cost	0.0	0.0
Net actuarial (loss) gain	0.4	0.4
Accumulated Other Comprehensive (Loss) Income	0.4	0.4
Components of the net periodic benefit cost (credit)
Service cost	0.0	0.1	0.0
Interest cost	0.3	0.3	0.4
Expected return on plan assets	0.0	0.0	0.0
Amortization of net actuarial loss (gain)	(0.1)	0.0	0.0
Net periodic benefit cost (credit)	0.2	0.4	0.4
Curtailment	0.0	0.0	0.0
Settlement	0.0	0.0	0.0
Net benefit cost (credit)	0.2	0.4	0.4
Changes in Accumulated Other Comprehensive Loss:
Prior service cost	0.0	0.0	0.0
Net actuarial loss (gain)	(0.1)	(0.5)	(0.5)
Amortization of net actuarial (loss) gain	0.1	0.0	0.0
Settlement	0.0	0.0	0.0
Total recognized in other comprehensive (loss) income	0.0	(0.5)	(0.5)
Total recognized in net benefit cost (credit) and other comprehensive loss (income)	0.2	$ (0.1)	$ (0.1)
Expected future benefit payments
2020	0.7
2021	0.7
2022	0.7
2023	0.7
2024	0.6
2025 to 2029	2.8
Total	6.2
Amounts that will be amortized from Accumulated Other Comprehensive Loss in next fiscal year
Net actuarial loss	$ 0.0
U.S. Nonqualified Plan | Pension Plan
Weighted-average assumptions used to determine benefit obligation
Discount rate	3.01%	3.95%
Rate of compensation increase	0.00%	0.00%
Weighted-average assumptions used to determine net periodic benefit costs
Discount rate	3.95%	3.28%	3.92%
Expected long-term rate of return on plan assets	0.00%	0.00%	5.10%
Rate of compensation increase	0.00%	0.00%	0.00%
Accumulated benefit obligations
Accumulated benefit obligations	$ 1.3	$ 1.3
Change in benefit obligation:
Benefit obligation at beginning of year	1.3	1.5
Service cost	0.0	0.0	$ 0.0
Interest cost	0.1	0.0	1.5
Plan amendments	0.0	0.0
Actuarial loss (gain)	0.0	0.0
Foreign exchange	0.0	0.0
Benefits paid	(0.1)	(0.2)
Settlement	0.0	0.0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0.0	0.0
Benefit obligation at end of year	1.3	1.3	1.5
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contributions	0.1	0.2
Foreign exchange	0.0	0.0
Benefits paid	(0.1)	(0.2)
Settlement	0.0	0.0
Fair value of plan assets at end of year	0.0	0.0	0.0
Funded status at end of year	(1.3)	(1.3)
Amounts recognized in the Consolidated Balance Sheets consist of:
Noncurrent Other Assets	0.0	0.0
Current Liabilities	(0.2)	(0.2)
Long-Term Liabilities	(1.1)	(1.1)
Net accrued (liability) asset	(1.3)	(1.3)
Amounts recognized in Accumulated Other Comprehensive Loss consist of:
Prior service cost	0.0	0.0
Net actuarial (loss) gain	(0.9)	(0.9)
Accumulated Other Comprehensive (Loss) Income	(0.9)	(0.9)
Components of the net periodic benefit cost (credit)
Service cost	0.0	0.0	0.0
Interest cost	0.1	0.0	1.5
Expected return on plan assets	0.0	0.0	(2.3)
Amortization of net actuarial loss (gain)	0.0	0.1	0.0
Net periodic benefit cost (credit)	0.1	0.1	(0.8)
Curtailment	0.0	0.0	0.0
Settlement	0.0	0.0	6.4
Net benefit cost (credit)	0.1	0.1	5.6
Changes in Accumulated Other Comprehensive Loss:
Prior service cost	0.0	0.0	0.0
Net actuarial loss (gain)	0.1	0.0	1.6
Amortization of net actuarial (loss) gain	0.0	(0.1)	0.0
Settlement	0.0	0.0	(6.4)
Total recognized in other comprehensive (loss) income	0.1	(0.1)	(4.8)
Total recognized in net benefit cost (credit) and other comprehensive loss (income)	0.2	$ 0.0	$ 0.8
Expected future benefit payments
2020	0.2
2021	0.1
2022	0.1
2023	0.1
2024	0.1
2025 to 2029	0.5
Total	$ 1.1
Foreign Plan | Pension Plan
Weighted-average assumptions used to determine benefit obligation
Discount rate	2.03%	2.72%
Rate of compensation increase	0.00%	3.50%
Weighted-average assumptions used to determine net periodic benefit costs
Discount rate	2.72%	2.45%	2.64%
Expected long-term rate of return on plan assets	3.80%	3.80%	3.90%
Rate of compensation increase	0.00%	3.50%	3.50%
Change in benefit obligation:
Benefit obligation at beginning of year	$ 10.2	$ 12.1
Service cost	0.0	0.1	$ 0.1
Interest cost	0.3	0.3	0.3
Plan amendments	0.0	0.1
Actuarial loss (gain)	0.8	(0.5)
Foreign exchange	(0.3)	0.6
Benefits paid	(0.2)	(1.2)
Settlement	0.0	0.0
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0.0
Benefit obligation at end of year	11.4	10.2	12.1
Change in fair value of plan assets and net accrued liabilities:
Fair value of plan assets at beginning of year	10.8	11.2
Actual return on plan assets	0.8	1.1
Employer contributions	0.4	0.3
Foreign exchange	0.4	(0.6)
Benefits paid	(0.2)	(1.2)
Settlement	0.0	0.0
Fair value of plan assets at end of year	12.2	10.8	11.2
Funded status at end of year	0.8	0.6
Amounts recognized in the Consolidated Balance Sheets consist of:
Noncurrent Other Assets	1.8	1.6
Current Liabilities	0.0	(0.1)
Long-Term Liabilities	(1.0)	(0.9)
Net accrued (liability) asset	0.8	0.6
Amounts recognized in Accumulated Other Comprehensive Loss consist of:
Prior service cost	(0.1)	(0.1)
Net actuarial (loss) gain	(0.4)	0.0
Accumulated Other Comprehensive (Loss) Income	(0.5)	(0.1)
Components of the net periodic benefit cost (credit)
Service cost	0.0	0.1	0.1
Interest cost	0.3	0.3	0.3
Expected return on plan assets	(0.4)	(0.4)	(0.4)
Amortization of net actuarial loss (gain)	0.0	0.0	0.1
Net periodic benefit cost (credit)	(0.1)	0.0	0.1
Curtailment	0.0	(0.1)	0.0
Settlement	0.0	0.0	0.0
Net benefit cost (credit)	(0.1)	(0.1)	0.1
Changes in Accumulated Other Comprehensive Loss:
Prior service cost	0.0	0.1	0.0
Net actuarial loss (gain)	0.4	(1.2)	(0.5)
Amortization of net actuarial (loss) gain	0.0	0.0	(0.1)
Settlement	0.0	0.0	0.0
Total recognized in other comprehensive (loss) income	0.4	(1.1)	(0.6)
Total recognized in net benefit cost (credit) and other comprehensive loss (income)	0.3	(1.2)	$ (0.5)
Expected future benefit payments
2020	0.2
2021	0.3
2022	0.3
2023	0.3
2024	0.3
2025 to 2029	1.6
Total	3.0
German Pension Plan | Foreign Plan | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contributions in the next fiscal year	0.1
Accumulated benefit obligations
Accumulated benefit obligations	1.0	0.9
U.K. Pension Plan | Foreign Plan
Change in benefit obligation:
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		0.1
U.K. Pension Plan | Foreign Plan | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contributions in the next fiscal year	0.3
Accumulated benefit obligations
Accumulated benefit obligations	10.4	$ 9.3
Retiree Plan | U.S. Nonqualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contributions in the next fiscal year	0.7
Nonqualified Plan | U.S. Nonqualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans
Expected future employer contributions in the next fiscal year	$ 0.2