Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) subsidiary segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Basis of Consolidation:
Number of operating segments | segment	1
Number of trust preferred subsidiaries | subsidiary	3
Premises and Equipment:
Premises and equipment, capitalization threshold	$ 5		$ 2
Deposits:
Related party deposit	61,800	$ 120,300
New Accounting Pronouncement:
Share-based compensation, excess tax benefit		$ 556
Contractual obligation	$ 19,900
Contractual lease, percentage of total assets	0.43%
Building | Minimum
Premises and Equipment:
Estimated useful life	20 years
Building | Maximum
Premises and Equipment:
Estimated useful life	39 years
Furniture and Equipment | Minimum
Premises and Equipment:
Estimated useful life	3 years
Furniture and Equipment | Maximum
Premises and Equipment:
Estimated useful life	15 years
Commercial
Allowance for Loan Losses:
Loans, nonaccrual status, outstanding balance requiring monthly review to determine allowance required, minimum	$ 50
Core Deposits
Valuation of Goodwill, Intangible Assets and Other Purchase Accounting Adjustments:
Finite lived intangible asset useful life	10 years