Business Segment Information (Schedule Of Total Assets By Reportable Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total consolidated assets	$ 5,665,811	$ 5,459,599
Onshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	668,740	614,484
Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,622,230	2,623,478
Refinery services
Segment Reporting Information [Line Items]
Total consolidated assets	389,292	394,626
Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	793,499	777,952
Supply and logistics
Segment Reporting Information [Line Items]
Total consolidated assets	1,138,443	1,000,851
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 53,607	$ 48,208