Savings Plans, Pension Plans and Other Postretirement Employee Benefits (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Sales and settlements		$ 10,600
401(K) contributions by employer	$ 2,100	2,000	$ 1,800
Pension Contributions	0	3,550	$ 0
Accumulated benefit obligation	375,500	$ 410,400
Non-Qualified Pension Plan, Estimated Payments in Next Fiscal Year	$ 1,800
Health care cost trend rate assumed for next fiscal year	7.70%
Decrease in accumulated postretirement benefit obligations				$ 76,700
Defined Benefit Plan, Assumption Health Care Cost Trend Rate for Next Fiscal Year	4.40%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	4.65%	4.25%	5.10%
Contributions	$ 1,811	$ 5,317
Estimated net loss to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	15,700
Estimated prior service cost to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	$ 500
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	4.25%	3.90%	4.45%
Contributions	$ 3,790	$ 4,319
Estimated net loss to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	1,700
Estimated prior service cost to be amortized from Accumulated Other Comprehensive Loss into Net Periodic Benefit Cost	$ 8,900