Allowance for Loan Losses - Additional Information (Details) - Loans [Member] - Bank shares, Inc [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Assets, Fair Value Adjustment	$ 17.4	$ 19.4
Fair value adjustment Percent	2.10%	2.20%

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.

No definition available.

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