Investment securities - Summary of Sales and Other Dispositions of Securities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 8,855	$ 146,494	$ 24,498
Proceeds from maturities, prepayments and calls	296,256	220,549	113,018
Gross realized gains	127	1,606	7
Gross realized losses	$ 1	$ 271	$ 98

Amount of realized gain 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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
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Amount of realized loss on 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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Amount of cash inflow from maturity, prepayment and call of 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 45
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Amount of cash inflow from sale of 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 45
-Paragraph 11
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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