Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net income (loss)	$ 230,347	$ 43,545	$ (61,911)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Deferred income taxes	36,854	(4,306)	(4,778)
Depreciation and amortization of property, plant and equipment	66,937	68,689	69,581
Amortization of intangible and other assets	1,082	1,254	1,260
Net loss on extinguishments of debt	113	10,259
Amortization of debt issuance costs, including discounts and premiums	2,073	6,067	3,807
Stock-based compensation	4,025	5,516	1,761
Loss (gain) associated with commodity contracts		(2,706)	1,613
Other	(4,638)	2,653	910
Cash provided (used) by changes in assets and liabilities:
Accounts receivable	10,197	(42,913)	(4,702)
Inventories	(14,300)	3,261	3,550
Supplies, prepaid items and other	(8,548)	(8,642)	(6,585)
Accounts payable	18,821	932	(6,561)
Other assets and other liabilities	2,691	4,018	(458)
Net cash provided (used) by operating activities	345,654	87,627	(2,513)
Cash flows from investing activities
Expenditures for property, plant and equipment	(45,833)	(35,128)	(30,471)
Proceeds from short-term investments	158,879
Purchases of short-term investments	(486,091)
Proceeds from vendor settlements associated with property, plant and equipment			1,647
Other investing activities	3,310	434	398
Net cash used by investing activities	(369,735)	(34,694)	(28,426)
Cash flows from financing activities
Proceeds from revolving debt facility		12,000	30,000
Payments on revolving debt facility		(12,000)	(30,000)
Proceeds from other long-term debt			42,570
Payments on other long-term debt	(13,750)	(10,472)	(21,356)
Payments of debt-related costs, including extinguishment costs	(4,840)	(27,254)	(124)
Proceeds from short-term financing	20,143	16,689	14,589
Payments on short-term financing	(16,725)	(17,549)	(10,941)
Payments of costs to exchange redeemable preferred stocks for common stock	(135)	(7,363)
Acquisition of treasury stock	(174,975)
Taxes paid on equity awards	(4,012)	(4,228)	(326)
Payments of dividends on non-redeemable preferred stocks		(1,876)
Net cash provided by financing activities	5,706	12,947	24,412
Net increase (decrease) in cash and cash equivalents	(18,375)	65,880	(6,527)
Cash and cash equivalents at beginning of year	82,144	16,264	22,791
Cash and cash equivalents at end of year	63,769	82,144	$ 16,264
6.25% Senior Secured Notes due 2028 [Member]
Cash flows from financing activities
Proceeds from 6.25% senior secured notes	$ 200,000	500,000
9.625% Senior Secured Notes due 2023 [Member]
Cash flows from financing activities
Payments on 9.625% senior secured notes		$ (435,000)