Derivatives (Fair Value of Derivative Assets And Liabilities) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Total asset derivatives		$ 0	$ 1,315
Current Assets-Other [Member] | Commodity Derivatives [Member] | Not Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		443	1,703
Derivative Asset, Fair Value, Gross Liability		(443)	(388)
Derivative Asset		0	1,315
Derivative Liability, Fair Value, Gross Liability	[1]	(1,772)	(388)
Derivative Liability, Fair Value, Gross Asset	[1]	1,772	388
Derivative Liability		0	0
Current Assets-Other [Member] | Commodity Derivatives [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		3,321	0
Derivative Asset, Fair Value, Gross Liability		(3,321)	0
Derivative Asset		0	0
Derivative Liability, Fair Value, Gross Liability	[1]	(9,506)	(23)
Derivative Liability, Fair Value, Gross Asset	[1]	7,589	23
Derivative Liability		$ (1,917)	$ 0

[1] These derivative liabilities have been funded with margin deposits recorded in our Consolidated Balance Sheets under Current Assets - Other.