Summary Of Significant Accounting Policies (Schedule Of Segment's Revenues) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Sunoco Logistics Partners L.P. | Oil and Natural Gas [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	24.00%	19.00%	14.00%
Valero Energy Corporation | Oil and Natural Gas [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	11.00%	15.00%	24.00%
QEP Resources, Inc. | Drilling [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	28.00%	25.00%	19.00%
Whiting Petroleum Corp. (formerly Kodiak Oil and Gas Corp.) | Drilling [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	18.00%	7.00%	9.00%
ONEOK Partners, L.P. | Mid-Stream [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	30.00%	29.00%	44.00%
Koch Energy Services, LLC [Member] | Mid-Stream [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	11.00%	9.00%	2.00%
Range Resources Corporation [Member] | Mid-Stream [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	10.00%	5.00%	2.00%
Tenaska Resources, LLC | Mid-Stream [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	10.00%	18.00%	22.00%
Laclede Group, Inc. | Mid-Stream [Member]
Revenue, Major Customer [Line Items]
Segment's revenues	9.00%	12.00%	16.00%