Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net periodic benefit cost for both the Executive Retirement Plan and the Outside Director Plan
Service cost			$ 29
Interest cost			225
Amortization of prior service cost (benefit)			(198)
Amortization of net gain			343
Total			399
Net loss recognized in Accumulated other comprehensive income (loss)	$ 0	$ 0	0
Total recognized in net periodic benefit gain and Accumulated other comprehensive income (1)			$ 399