Summary Of Significant Accounting Policies (Schedule Of Segment's Revenues) (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Sunoco Logistics Partners L.P. | Oil and Natural Gas
Revenue, Major Customer [Line Items]
Segment's revenues	19.00%	14.00%	8.00%
Valero Energy Corporation | Oil and Natural Gas
Revenue, Major Customer [Line Items]
Segment's revenues	15.00%	24.00%	25.00%
QEP Resources, Inc. | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	25.00%	19.00%	18.00%
Whiting Petroleum Corp. (formerly Kodiak Oil and Gas Corp.) | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	7.00%	9.00%	10.00%
ONEOK Partners, L.P. | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	29.00%	44.00%	57.00%
Tenaska Resources, LLC | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	18.00%	22.00%	16.00%
Laclede Group, Inc. | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	12.00%	16.00%	7.00%