Fair value measurement - Schedule of Fair Value of Pension Plan Assets by Level within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	$ 386,108
Retirement Plans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	386,108	$ 385,005	$ 541,758
Retirement Plans | Cash and other | Fair Value, Inputs, Level 1, 2 and 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	87
Retirement Plans | Cash and other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	87
Retirement Plans | Cash and other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	0
Retirement Plans | Cash and other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	0
Retirement Plans | Common collective trust - equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets		54,917
Retirement Plans | Common collective trust - equities | Fair Value, Inputs, Level 1, 2 and 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	67,314
Retirement Plans | Common collective trust - fixed income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets		329,821
Retirement Plans | Common collective trust - fixed income | Fair Value, Inputs, Level 1, 2 and 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	318,594
Retirement Plans | Partnership/joint venture interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets		$ 267
Retirement Plans | Partnership/joint venture interests | Fair Value, Inputs, Level 1, 2 and 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of plan assets	$ 113