Consolidated Statements of Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Held to maturity securities, fair value	$ 46,935	$ 19,220	$ 17,859
Common stock, par value	$ 1	$ 1	$ 1
Common stock, shares authorized	15,000,000	15,000,000	15,000,000
Common stock, shares issued	5,123,186	5,123,186	5,123,186
Common stock, shares outstanding	5,123,186	5,123,186	5,123,186