Post-retirement Plan (Net Periodic Pension Expense) (Details) - Other Postretirement Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost - benefit earned during the period	$ 324	$ 424
Interest cost on projected benefit obligations	197	205
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(871)	(871)
Defined Benefit Plan, Amortization of Gains (Losses)	0	46
Net periodic post-retirement expense (credit)	$ (350)	$ (196)