Equity-Based Compensation Plans (Expense Related To Equity-Based Compensation Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expense related to equity-based compensation plan	$ (4,577)	$ 8,580	$ 6,922
Onshore facilities and transportation operating costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expense related to equity-based compensation plan	(1,137)	1,688	1,185
Marine transportation operating costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expense related to equity-based compensation plan	(483)	1,089	851
Sodium minerals and sulfur services operating costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expense related to equity-based compensation plan	(533)	547	227
Offshore pipeline operating costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expense related to equity-based compensation plan	(152)	681	94
General and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expense related to equity-based compensation plan	$ (2,272)	$ 4,575	$ 4,565