Employee Benefit Plans (Schedule of Amounts Expected to be Amortized from Regulatory Assets to Net Periodic Benefit Cost) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Pension Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial Loss	$ 1,566
Prior Service Credit
Other Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial Loss	1,781
Prior Service Credit	$ (1,728)