Retirement Benefit Plans - Assets Measured at Fair Value (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Foreign Plan [Member]
Assets:
Total Assets	$ 254.6	$ 292.4	$ 268.7
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	254.6	292.4
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	0.8	4.8
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | International Equity Securities [Member]
Assets:
Total Assets	2.2	1.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Common Collective funds - domestic equities [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Common collective funds - international equities [Member]
Assets:
Total Assets	13.6	25.3
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Fixed Income Funds [Member]
Assets:
Total Assets	76.2	86.2
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Limited Partnership [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Real Estate [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Hedge Funds [Member]
Assets:
Total Assets	122.9	132.5
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Defined Benefit Plan, Common Collective Trust [Member]
Assets:
Total Assets	18.5	21.2
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Other Assets [Member]
Assets:
Total Assets	20.4	21.3
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents at Net Asset Value [Member]
Assets:
Total Assets	0.0	0.1
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	0.8	4.8
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	0.8	4.8
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.0
Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.0
Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.0
Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Foreign Plan [Member] | Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	0.8	4.8
Domestic Plan [Member]
Assets:
Total Assets	448.3	531.9	$ 529.6
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	448.3	531.9
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	18.6	27.2
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	32.6	18.9
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	71.7	105.1
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | International Equity Securities [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Common Collective funds - domestic equities [Member]
Assets:
Total Assets	54.0	37.0
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Common collective funds - international equities [Member]
Assets:
Total Assets	9.4	11.5
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Fixed Income Funds [Member]
Assets:
Total Assets	137.3	220.9
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Limited Partnership [Member]
Assets:
Total Assets	24.0	31.8
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Real Estate [Member]
Assets:
Total Assets	11.8	16.9
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Hedge Funds [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Defined Benefit Plan, Common Collective Trust [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Other Assets [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	60.8	44.9
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.1
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	24.0	17.5
Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents at Net Asset Value [Member]
Assets:
Total Assets	0.2	0.2
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	137.2	105.1
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	18.6	27.2
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	29.9	15.5
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	60.8	44.9
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.1
Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	24.0	17.5
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	74.4	108.5
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	2.7	3.4
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	71.7	105.1
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.0
Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Cash and cash equivalents [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Government and agency securities [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Other Debt Obligations [Member]
Assets:
Total Assets	0.0
Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0	0.0
Domestic Plan [Member] | Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Total Assets	211.6	$ 213.6
Equity Option [Member] | Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Equity Option [Member] | Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Equity Option [Member] | Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Equity Option [Member] | Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Equity Option [Member] | Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	2.6
Equity Option [Member] | Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	2.6
Equity Option [Member] | Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Equity Option [Member] | Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Other Debt Obligations [Member] | Foreign Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Other Debt Obligations [Member] | Foreign Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Other Debt Obligations [Member] | Foreign Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Other Debt Obligations [Member] | Foreign Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Other Debt Obligations [Member] | Domestic Plan [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	1.2
Other Debt Obligations [Member] | Domestic Plan [Member] | Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	1.2
Other Debt Obligations [Member] | Domestic Plan [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	0.0
Other Debt Obligations [Member] | Domestic Plan [Member] | Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mutual Fund [Member]
Assets:
Total Assets	$ 0.0