Retirement Benefit Plans - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Amounts recognized on the Consolidated Balance Sheets:
Non-current assets	$ 3.4	$ 6.2
Total	36.6	0.0
Pension Plan [Member]
Amounts recognized on the Consolidated Balance Sheets:
Current liabilities	6.9	28.9
UNITED STATES | Pension Plan [Member]
Amounts recognized on the Consolidated Balance Sheets:
Non-current assets	0.0	0.0
Current liabilities	5.4	27.4
Non-current liabilities	(109.1)	(110.9)
Total	(114.5)	(138.3)
Foreign Plan [Member] | Pension Plan [Member]
Amounts recognized on the Consolidated Balance Sheets:
Non-current assets	3.4	6.2
Current liabilities	1.5	1.5
Non-current liabilities	(56.0)	(50.4)
Total	$ (54.1)	$ (45.7)