Changes in accumulated other comprehensive income - Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Benefit (expense) from income taxes	$ (45,608)	$ (45,643)
Reclassification out of Accumulated Other Comprehensive Income \| Amounts reclassified from accumulated other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net unrealized gains (losses) on investments	(5,810)	(3,128)
Benefit (expense) from income taxes	$ 1,220	$ 657

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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+ Details