Business Segment Information (Schedule Of Total Assets By Reportable Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total consolidated assets	$ 5,640,376	$ 5,702,592
Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,514,688	2,575,335
Refinery services
Segment Reporting Information [Line Items]
Total consolidated assets	391,208	395,043
Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	798,835	813,722
Onshore facilities and transportation
Segment Reporting Information [Line Items]
Total consolidated assets	1,878,944	1,875,403
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 56,701	$ 43,089