Derivatives and Financial Instruments - Fair Values of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Revolving credit facility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	$ 43.1	$ 31.9
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:	43.1	31.9
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
Bank overdraft
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	4.6
Bank overdraft \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0
Bank overdraft \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	4.6
Bank overdraft \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:	0.0
Loan Notes \| 4.94% Loan Notes due June 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 \| 4.94% Loan Notes due June 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 \| 4.94% Loan Notes due June 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 \| 4.94% Loan Notes due June 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
Loan Notes \| 4.88% Loan Notes due June 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:		25.0
Loan Notes \| 4.88% Loan Notes due June 2023 \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:		0.0
Loan Notes \| 4.88% Loan Notes due June 2023 \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:		25.0
Loan Notes \| 4.88% Loan Notes due June 2023 \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest bearing loans and borrowings:		0.0
Foreign currency contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.4	0.7
Foreign currency contract liabilities		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
Foreign currency contract \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.4	0.7
Foreign currency contract liabilities		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