Accumulated Other Comprehensive Income (Loss) Accumulated Other comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	$ (5,676)	$ (2,533)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(636)	(3,724)
Amounts reclassified from accumulated other comprehensive loss	472	581
Net current-period other comprehensive gain/(loss)	(164)	(3,143)
Accumulated other comprehensive loss at end of period	(5,840)	(5,676)
UnrealizedGainsLossesFromDefinedBenefitPensionAndPostretirementPlanItems [Member]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	(5,643)	(2,533)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(286)	(3,242)
Amounts reclassified from accumulated other comprehensive loss	349	132
Net current-period other comprehensive gain/(loss)	63	(3,110)
Accumulated other comprehensive loss at end of period	(5,580)	(5,643)
Accumulated (Gain) Loss from Commodity Contracts Cash Flows Hedges [Member]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax [Roll Forward]
Accumulated other comprehensive loss at beginning of period	(33)	0
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(350)	(482)
Amounts reclassified from accumulated other comprehensive loss	123	449
Net current-period other comprehensive gain/(loss)	(227)	(33)
Accumulated other comprehensive loss at end of period	$ (260)	$ (33)