Loans - Troubled Debt Restructuring (Narrative) (Details) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2021 USD ($) loan	Mar. 31, 2020 USD ($) loan	Dec. 31, 2020 USD ($)
Financing Receivable, Impaired [Line Items]
Average recorded investment	$ 7,966	$ 2,780
Impaired financing receivable, related allowance	3,551		$ 4,107
Financing receivable, nonaccrual status	$ 11,788		12,060
Number of loans modified as a TDR \| loan	2	0
Number of loans modified as TDR, subsequent default \| loan	0
Number of loans modified as TDRs \| loan	2	0
Troubled Debt Restructuring (TDR)
Financing Receivable, Impaired [Line Items]
Impaired loan reserve	$ 0
Troubled Debt Restructuring (TDR) \| Performing
Financing Receivable, Impaired [Line Items]
Average recorded investment	$ 1,100		$ 663

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Number of financing receivables that have been modified by troubled debt restructurings.

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Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

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Amount of financing receivable on nonaccrual status.

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of allowance for credit losses related to recorded investment.

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