Investments in debt and equity securities - Schedule of Amortized Costs and Fair Values of Investments in Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]
Amortized costs	$ 554,257	$ 558,544
Fair values	551,941	558,488
Municipal
Debt Securities, Available-for-sale [Line Items]
Amortized costs	8,912	12,292
Fair values	8,908	12,274
Corporate
Debt Securities, Available-for-sale [Line Items]
Amortized costs	142,084	144,571
Fair values	139,362	143,621
Foreign
Debt Securities, Available-for-sale [Line Items]
Amortized costs	338,647	347,588
Fair values	339,639	348,084
U.S. Treasury Bonds
Debt Securities, Available-for-sale [Line Items]
Amortized costs	64,614	54,093
Fair values	$ 64,032	$ 54,509

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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