Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 55	$ 51
Expected return on plan assets	(65)	(77)
Amortization of the net loss	22	17
Net periodic cost (benefit)	12	(9)
Contributions to defined benefit pension plan	0
Expected contribution to pension plan in 2016	140
Supplemental Executive Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	47	48
Interest cost	36	37
Amortization of prior service cost	8	7
Amortization of the net loss	34	31
Net periodic cost (benefit)	$ 125	$ 123