Derivatives and Financial Instruments - Fair Values of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract liabilities	$ 0.1	$ 0.4
Revolving credit facility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	10.8	4.1
Revolving credit facility \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0	0.0
Revolving credit facility \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	10.8	4.1
Revolving credit facility \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0	0.0
Loan Notes \| Loan Notes due 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	25.0	25.0
Loan Notes \| Loan Notes due 2023 \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0	0.0
Loan Notes \| Loan Notes due 2023 \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	25.0	25.0
Loan Notes \| Loan Notes due 2023 \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0	0.0
Loan Notes \| Loan Notes due 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	25.0	25.0
Loan Notes \| Loan Notes due 2026 \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0	0.0
Loan Notes \| Loan Notes due 2026 \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	25.0	25.0
Loan Notes \| Loan Notes due 2026 \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0	0.0
Foreign currency contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.1	0.2
Foreign currency contract liabilities	0.1	0.4
Foreign currency contract \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.0	0.0
Foreign currency contract liabilities	0.0	0.0
Foreign currency contract \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.1	0.2
Foreign currency contract liabilities	0.1	0.4
Foreign currency contract \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.0	0.0
Foreign currency contract liabilities	$ 0.0	$ 0.0