Fair Value of Assets and Liabilities (Details 6) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Total debt securities, Fair Value	$ 141,717	$ 162,422
Minimum
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate	8.60%	9.10%
Maximum
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate	11.70%	14.74%
Trust preferred securities
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Total debt securities, Fair Value	$ 1,090	$ 895
Trust preferred securities | Minimum
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate		0.00%
Trust preferred securities | Maximum
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate		14.74%
Trust preferred securities | Discounted Cash Flow
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Total debt securities, Fair Value	$ 1,090	$ 895
Impaired Loans | Minimum
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate		4.50%
Impaired Loans | Maximum
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate		5.38%
Impaired Loans | Weighted average
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Fair value input discount rate		4.88%
Impaired Loans | Appraisal Of Collateral
Significant unobservable inputs for assets and liabilities measured at fair value on a recurring and nonrecurring basis
Total debt securities, Fair Value		$ 4,891