Business Segment Information (Schedule Of Total Assets By Reportable Segment) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total consolidated assets	$ 5,569,374	$ 5,459,599
Onshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	645,791	614,484
Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,647,679	2,623,478
Refinery services
Segment Reporting Information [Line Items]
Total consolidated assets	390,893	394,626
Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	778,042	777,952
Supply and logistics
Segment Reporting Information [Line Items]
Total consolidated assets	1,051,590	1,000,851
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 55,379	$ 48,208