Pension and Other Post-Retirement Benefit Plans (Accumulated Other Comprehensive Income (Loss) to be Recognized within 12 Months) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Pension Plans [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Amortization of actuarial loss	$ 7,746
Prior Service Cost	0
Post-Retirement Healthcare Plans [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Amortization of actuarial loss	283
Prior Service Cost	$ (51)