Investments in debt and equity securities - Gross Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Gains	$ 2,611	$ 14,319
Losses	16,426	2,712
Municipal
Debt Securities, Available-for-sale [Line Items]
Gains	278	1,585
Losses	30	1
Corporate
Debt Securities, Available-for-sale [Line Items]
Gains	1,778	9,389
Losses	5,841	1,044
Foreign
Debt Securities, Available-for-sale [Line Items]
Gains	534	3,285
Losses	10,489	1,642
U.S. Treasury Bonds
Debt Securities, Available-for-sale [Line Items]
Gains	21	60
Losses	$ 66	$ 25

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

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- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

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