Goodwill and Other Intangible Assets (Changes in Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Goodwill at beginning of period	$ 129,342	$ 129,342	$ 131,542
Disposals	(800)		(2,200)
Acquisitions		0
Impairments	(686)
Goodwill at end of period	127,856	129,342	129,342
Trade
Goodwill [Roll Forward]
Goodwill at beginning of period	119,867	119,867	122,067
Disposals	(800)		(2,200)
Acquisitions		0
Impairments	0
Goodwill at end of period	119,067	119,867	119,867
Renewables
Goodwill [Roll Forward]
Goodwill at beginning of period	8,789	8,789	8,789
Disposals	0		0
Acquisitions		0
Impairments	0
Goodwill at end of period	8,789	8,789	8,789
Nutrient & Industrial
Goodwill [Roll Forward]
Goodwill at beginning of period	686	686	686
Disposals	0		0
Acquisitions		0
Impairments	(686)
Goodwill at end of period	$ 0	$ 686	$ 686