Transactions With Related Parties (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Sandhill Group LLC
Related Party Transaction [Line Items]
Due from related parties	$ 200		$ 200
Revenue from Related Parties	677	$ 726
Poseidon Oil Pipeline Company
Related Party Transaction [Line Items]
Due from related parties	2,000		$ 1,600
Revenue from Related Parties	3,022	$ 1,976
Management Fees Revenue	$ 2,097

For an unclassified balance sheet, amounts due from related parties including affiliates, employees, joint ventures, officers and stockholders, immediate families thereof, and pension funds.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=16382449

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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