Retirement Benefit Plans - Assumptions (Details) - Pension Plan [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets			6.00%
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	5.92%
Assumptions:
Discount rate	4.34%
Domestic Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	5750000.00%	5.75%
Assumptions:
Discount rate	4.34%	4.50%	3.98%
Future compensation assumption	2.50%	3.00%	2.00%
Domestic Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	6500000.00%	6.75%
Assumptions:
Discount rate	4.50%	4.70%	4.64%
Future compensation assumption	3.00%	3.00%	3.00%
Foreign Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	0.75%	0.82%	2.25%
Assumptions:
Discount rate	1.25%	2.00%	1.50%
Future compensation assumption	2.00%	2.20%	2.20%
Foreign Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets	9.25%	9.25%	9.25%
Assumptions:
Discount rate	9.00%	8.50%	8.75%
Future compensation assumption	8.00%	8.00%	8.00%