Other comprehensive (loss) income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Before-Tax Amount
Other comprehensive (loss) income	$ (8,163)	$ 5,327	$ (15,077)	$ 14,606
Tax Expense (Benefit)
Other comprehensive (loss) income	(1,382)	738	(2,832)	3,231
Net-of-Tax Amount
Other comprehensive (loss) income, net of taxes:	(6,781)	4,589	(12,245)	11,375
Net unrealized gains and losses on investments
Before-Tax Amount
Change in net unrealized gains and losses on investments	(2,764)	1,164	(13,076)	19,056
Reclassification adjustment for realized gains and losses on investments	(449)	(221)	(1,162)	(349)
Other comprehensive (loss) income	(3,213)	943	(14,238)	18,707
Tax Expense (Benefit)
Change in net unrealized gains and losses on investments	(581)	244	(2,746)	4,001
Reclassification adjustment for realized gains and losses on investments	(94)	(46)	(244)	(73)
Other comprehensive (loss) income	(675)	198	(2,990)	3,928
Net-of-Tax Amount
Change in net unrealized gains and losses on investments	(2,183)	920	(10,330)	15,055
Reclassification adjustment for realized gains and losses on investments	(355)	(175)	(918)	(276)
Other comprehensive (loss) income, net of taxes:	(2,538)	745	(11,248)	14,779
Foreign currency translation adjustments
Before-Tax Amount
Other comprehensive (loss) income	(4,950)	4,384	(839)	(4,101)
Tax Expense (Benefit)
Other comprehensive (loss) income	(707)	540	158	(697)
Net-of-Tax Amount
Other comprehensive (loss) income, net of taxes:	$ (4,243)	$ 3,844	$ (997)	$ (3,404)