Other comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Before-Tax Amount
Other comprehensive income (loss)	$ 9,202	$ (24,446)
Tax Expense (Benefit)
Other comprehensive income (loss)	1,895	(4,983)
Net-of-Tax Amount
Other comprehensive income (loss)	7,307	(19,463)
Net unrealized gains and losses on investments
Before-Tax Amount
Change in net unrealized gains and losses on investments	8,376	(25,188)
Reclassification adjustments for realized gains and losses on investments	116	(234)
Other comprehensive income (loss)	8,492	(25,422)
Tax Expense (Benefit)
Change in net unrealized gains and losses on investments	1,759	(5,290)
Reclassification adjustments for realized gains and losses on investments	24	(49)
Other comprehensive income (loss)	1,783	(5,339)
Net-of-Tax Amount
Change in net unrealized gains and losses on investments	6,617	(19,898)
Reclassification adjustments for realized gains and losses on investments	92	(185)
Other comprehensive income (loss)	6,709	(20,083)
Foreign currency translation adjustments
Before-Tax Amount
Other comprehensive income (loss)	710	976
Tax Expense (Benefit)
Other comprehensive income (loss)	112	356
Net-of-Tax Amount
Other comprehensive income (loss)	$ 598	$ 620