Summary Of Significant Accounting Policies (Schedule Of Segment's Revenues) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valero Energy Corporation | Oil and Natural Gas
Revenue, Major Customer [Line Items]
Segment's revenues	24.00%	25.00%	26.00%
Sunoco Partners Marketing | Oil and Natural Gas
Revenue, Major Customer [Line Items]
Segment's revenues	14.00%	8.00%	8.00%
QEP Resources, Inc. | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	19.00%	18.00%	15.00%
Whiting Petroleum Corp. (formerly Kodiak Oil and Gas Corp.) | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	9.00%	10.00%	10.00%
ONEOK Partners, L.P. | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	44.00%	57.00%	54.00%
Tenaska Resources, LLC | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	22.00%	16.00%	7.00%
Laclede Gas Company | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	10.00%	2.00%	0.00%
Gavilon, LLC | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	0.00%	0.00%	10.00%