The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Section S99
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Transactions With Related Parties (Schedule Of Transactions With Related Parties) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Sandhill [Member]
Related Party Transaction [Line Items]
Related party transaction, revenues	$ 762	$ 806
Sandhill Group LLC
Related Party Transaction [Line Items]
Related party transaction, revenues			$ 1,488	$ 1,505
Poseidon Oil Pipeline Company
Related Party Transaction [Line Items]
Related party transaction, revenues	1,980	0	3,956	0
Related party transaction, expenses	251	0	498	0
Chief Executive Officer
Related Party Transaction [Line Items]
Related party transaction, expenses	$ 165	$ 165	$ 330	$ 360
Poseidon Oil Pipeline Company
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage	64.00%		64.00%
Sandhill Group LLC
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%