Employee Benefit Plans - Fair value of plan assets by asset category (Details) $ in Thousands	Dec. 31, 2025 USD ($)
Fair value of plan assets by asset category
Aggregate fair value of plan assets	$ 55,406
Level 1
Fair value of plan assets by asset category
Aggregate fair value of plan assets	1,784
Level 2
Fair value of plan assets by asset category
Aggregate fair value of plan assets	53,622
Cash
Fair value of plan assets by asset category
Aggregate fair value of plan assets	1,784
Cash | Level 1
Fair value of plan assets by asset category
Aggregate fair value of plan assets	1,784
U.K. and other international equities
Fair value of plan assets by asset category
Aggregate fair value of plan assets	16,801
U.K. and other international equities | Level 2
Fair value of plan assets by asset category
Aggregate fair value of plan assets	16,801
Corporate bonds / U.K. Gilts
Fair value of plan assets by asset category
Aggregate fair value of plan assets	2,177
Corporate bonds / U.K. Gilts | Level 2
Fair value of plan assets by asset category
Aggregate fair value of plan assets	2,177
Diversified growth fund
Fair value of plan assets by asset category
Aggregate fair value of plan assets	11,846
Diversified growth fund | Level 2
Fair value of plan assets by asset category
Aggregate fair value of plan assets	11,846
Liability driven investments
Fair value of plan assets by asset category
Aggregate fair value of plan assets	19,728
Liability driven investments | Level 2
Fair value of plan assets by asset category
Aggregate fair value of plan assets	19,728
Multi-asset credit fund
Fair value of plan assets by asset category
Aggregate fair value of plan assets	3,070
Multi-asset credit fund | Level 2
Fair value of plan assets by asset category
Aggregate fair value of plan assets	$ 3,070