Acquisitions Summary of PCI Loan Portfolio (Details) - First Century Bankshares, Inc [Member] $ in Thousands	Apr. 01, 2017 USD ($)
Business Acquisition [Line Items]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Acquired During Period, Contractually Required Payments Receivable at Acquisition	$ 4,885
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Reclassifications to Nonaccretable Difference	(597)
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition	4,288
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield	(661)
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value	$ 3,627