Fixed Assets And Asset Retirement Obligations (Schedule Of Fixed Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Fixed Assets, at cost	$ 617,611	$ 541,138
Less: Accumulated depreciation	(131,928)	(124,213)
Net fixed assets	485,683	416,925
Land, Buildings And Improvements [Member]
Fixed Assets, at cost	13,207	13,140
Machinery And Equipment [Member]
Fixed Assets, at cost	47,342	46,233
Transportation Equipment [Member]
Fixed Assets, at cost	20,902	21,732
Marine Vessels [Member]
Fixed Assets, at cost	293,106	262,216
Pipelines And Related Assets [Member]
Fixed Assets, at cost	196,790	167,865
Property, Plant And Equipment, Other Types [Member]
Fixed Assets, at cost	12,048	11,938
Office Equipment, Furniture And Fixtures [Member]
Fixed Assets, at cost	4,072	3,778
Construction In Progress [Member]
Fixed Assets, at cost	$ 30,144	$ 14,236

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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