Securities - Summary of available-for-sale securities sales activity (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 39,365	$ 0	$ 40,365	$ 225,883
Gross gains on sales	746	0	746	1,776
Gross losses on sales	0	0	0	(1,894)
Net gains (losses) on sales of securities	746	0	746	(118)
Income tax expense (benefit) attributable to sales	$ 191	$ 0	$ 191	$ (30)

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).

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Amount of realized gain (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 tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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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).

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