Derivatives (Schedule of Effect on Operating Results) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Commodity derivatives - futures and call options | Cost of Goods and Services Sold
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ (3,342)	$ (13,578)	$ (13,160)	$ (14,224)
Natural Gas Swap | Cost of Goods and Services Sold | Sodium minerals and sulfur services operating costs
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	30	983	(37)	551
Preferred Distribution Rate Reset Election | Other income (expense)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(14,344)	(21,839)	(32,782)	10,706
Contracts designated as hedges under accounting guidance | Commodity derivatives - futures and call options | Cost of Goods and Services Sold | Onshore facilities and transportation product costs
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	(1,563)	(10,936)	(7,460)	(10,207)
Contracts not considered hedges under accounting guidance | Commodity derivatives - futures and call options | Cost of Goods and Services Sold | Onshore facilities and transportation product costs, Sodium minerals and sulfur services operating costs
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income	$ (1,779)	$ (2,642)	$ (5,700)	$ (4,017)