Pension and Postretirement Plans (Future Amortization of Net Periodic Cost) (Details 8) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss recognition	$ (5,161)
Prior service cost (credit) recognition	156
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss recognition	1,827
Prior service cost (credit) recognition	457
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss recognition	(3,953)
Prior service cost (credit) recognition	$ (291)