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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
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-Section 50
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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No definition available.

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EQUITY INVESTMENTS - Schedule of Equity Method Investment Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity investments
Total equity investments	$ 84,128	$ 82,849
Total earnings from equity investments	6,381	11,265	$ 5,243
Domestic Pipelines & Terminals
Equity investments
Total equity investments	84,128	82,849
West Shore Pipe Line Company
Equity investments
Total earnings from equity investments	$ 7,070	8,621	4,176
West Shore Pipe Line Company \| Domestic Pipelines & Terminals
Equity investments
Ownership	34.60%
Total equity investments	$ 60,441	57,123
Muskegon Pipeline LLC
Equity investments
Total earnings from equity investments	$ (2,876)	1,059	(77)
Muskegon Pipeline LLC \| Domestic Pipelines & Terminals
Equity investments
Ownership	40.00%
Total equity investments	$ 13,599	16,175
Transport4, LLC
Equity investments
Total earnings from equity investments	$ 606	470	361
Transport4, LLC \| Domestic Pipelines & Terminals
Equity investments
Ownership	25.00%
Total equity investments	$ 459	503
South Portland Terminal LLC
Equity investments
Total earnings from equity investments	$ 1,581	1,115	$ 783
South Portland Terminal LLC \| Domestic Pipelines & Terminals
Equity investments
Ownership	50.00%
Total equity investments	$ 9,629	$ 9,048