Allowance for Loan Losses - Narrative (Details) - Loans - Bank Shares, Inc - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Remaining fair value adjustment for loans acquired	$ 36.3	$ 47.0
Percentage of fair value adjustment for loans acquired	3.80%	3.90%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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