Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investment securities:
Held-to-maturity Securities, Fair Value	$ 68,457	$ 73,096
Stockholders Equity
Common stock, par value (in dollars per share)	$ 4	$ 4
Common stock, authorized (in shares)	18,000,000	18,000,000
Common stock, issued (in shares)	13,231,225	13,020,742
Treasury stock (in shares)	570,477	549,743