Securities - Narrative (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, accrued interest	$ 6,000,000		$ 4,400,000
Held to maturity, amortized cost	37,762,000
Held-to-maturity securities, nonaccrual status	0	$ 0
Total Past Due
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, amortized cost	$ 0	$ 0

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

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Amount of investment in debt security measured at amortized cost (held-to-maturity) on nonaccrual status.

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

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