Intangible Assets, Goodwill And Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
CO2 volumetric production payments, net of amortization		$ 3,503	$ 7,413
Deferred marine charges, net	[1]	27,710	23,646
Other deferred costs and deposits		25,398	27,633
Other assets, net of amortization		$ 56,611	$ 58,692

[1] (1)See discussion of deferred charges on marine transportation assets in the Summary of Accounting Policies (Note 2)