Income Taxes - Uncertain tax positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in unrecognized tax benefits
Balance as of January 1	$ 45,452	$ 45,988	$ 26,704
Additions for tax positions of prior years	2,207	806	19,760
Reductions for tax positions of prior years	(256)	(1,342)	(476)
Settlements	(13,387)
Balance as of December 31	34,016	45,452	45,988
Unrecognized tax benefits that would impact the worldwide effective tax rate if realized	34,000
Interest and penalties on unrecognized tax benefits	11,100	17,000	14,400
Accruals for estimated interest and penalties related to uncertain tax positions	(6,000)	2,600	$ 6,900
Interest accrued	13,400
Penalties	9,900
Deferred tax asset for Bermuda net operating losses	171,900
Valuation allowance	3,962,200	$ 3,839,885
Bermuda
Change in unrecognized tax benefits
Valuation allowance	$ 171,900