Other comprehensive (loss) income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Before-Tax Amount
Other comprehensive income (loss)	$ (17,027)	$ 17,159
Tax Expense (Benefit)
Other comprehensive income (loss)	(2,925)	3,398
Net-of-Tax Amount
Other comprehensive (loss) income, net of taxes:	(14,102)	13,761
Net unrealized (losses) gains on investments
Before-Tax Amount
Change in net unrealized gains and losses on investments	(3,267)	11,406
Less: reclassification adjustment for net losses (gains) included in net income	(101)	205
Other comprehensive income (loss)	(3,368)	11,611
Tax Expense (Benefit)
Change in net unrealized gains and losses on investments	(687)	2,395
Less: reclassification adjustment for net losses (gains) included in net income	(21)	43
Other comprehensive income (loss)	(708)	2,438
Net-of-Tax Amount
Change in net unrealized gains and losses on investments	(2,580)	9,011
Reclassification adjustment for realized gains and losses on investments	(80)	162
Other comprehensive (loss) income, net of taxes:	(2,660)	9,173
Foreign currency translation adjustments
Before-Tax Amount
Other comprehensive income (loss)	(13,659)	5,548
Tax Expense (Benefit)
Other comprehensive income (loss)	(2,217)	960
Net-of-Tax Amount
Other comprehensive (loss) income, net of taxes:	$ (11,442)	$ 4,588