Leases (Schedule Of Future Minimum Lease Payments Under Operating Leases) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Operating Leased Assets [Line Items]
2013	$ 100,758
2014	68,508
2015	56,108
2016	18,312
2017	13,841
Thereafter	28,001
Future minimum lease payments under operating leases	285,528
Marine Equipment [Member] | Tank Barges [Member]
Operating Leased Assets [Line Items]
2013	19,309
2014	17,125
2015	15,497
2016	11,984
2017	11,397
Thereafter	22,366
Future minimum lease payments under operating leases	97,678
Marine Equipment [Member] | Towing Vessels [Member]
Operating Leased Assets [Line Items]
2013	73,028
2014	44,011
2015	34,620
2016	3,137
2017	0
Thereafter	0
Future minimum lease payments under operating leases	154,796
Land Buildings and Equipment [Member]
Operating Leased Assets [Line Items]
2013	8,421
2014	7,372
2015	5,991
2016	3,191
2017	2,444
Thereafter	5,635
Future minimum lease payments under operating leases	$ 33,054