Investment securities - Summary of Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Amortized Cost of Held-to-maturity Securities
Amortized Cost, After five but within ten years, Held to maturity	$ 8,092
Amortized Cost, After ten years, Held to maturity	3,165
Amortized Cost, Held to maturity	11,257
Amortized Cost, Mortgage-backed securities, Held to maturity	83,189
Held-to-maturity, Amortized Cost	94,446	$ 71,213
Fair Value of Held-to-maturity Securities
Fair Value, After five but within ten years, Held to maturity	7,429
Fair Value, After ten years, Held to maturity	2,860
Fair Value, Held to maturity	10,289
Fair Value, Mortgage-backed securities, Held to maturity	73,787
Held to maturity, Fair Value	$ 84,076	$ 70,446

Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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