Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Revenues	$ 274,985	$ 320,671	$ 543,245	$ 548,798
Costs and expenses:
Cost of goods sold	239,332	282,473	459,737	494,633
Selling, general and administrative expenses	21,807	20,752	41,662	41,479
Environmental charge	0	0	490	0
Total costs and expenses	261,139	303,225	501,889	536,112
Operating income	13,846	17,446	41,356	12,686
Interest expense, net	(10,412)	(8,696)	(11,904)	(8,414)
Non-operating pension and other postretirement employee benefits	(351)	201	(702)	402
Other	741	(23)	535	(168)
Income before income taxes	3,824	8,928	29,285	4,506
Income taxes	3,530	4,750	3,874	8,867
Net income	$ 7,354	$ 13,678	$ 33,159	$ 13,373
Net income per share:
Basic	$ 0.09	$ 0.17	$ 0.42	$ 0.17
Diluted	0.09	0.17	0.42	0.17
Dividends per share	$ 0.45	$ 0.45	$ 0.9	$ 0.9
Weighted-average shares outstanding
Basic	78,280	79,627	78,643	79,656
Diluted	78,441	79,741	78,781	79,756