Fair value measurements - Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Auction rate securities - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 2,713	$ 31,682	$ 2,713	$ 31,776
Total realized and unrealized gain (losses)	3	3,153	3	3,159
Purchases and issuances	0	0	0	0
Sales and settlements	(35)	(32,122)	(35)	(32,222)
Transfers in (out)	0	0	0	0
Ending balance	$ 2,681	$ 2,713	$ 2,681	$ 2,713