CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities
Net income	$ 15,178	$ 40,996
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income taxes	2,321	7,736
Gain on extinguishment of debt	(3,013)	(8,644)
Depreciation and amortization of property, plant and equipment	35,861	34,416
Amortization of short term investments	5,630	(670)
Amortization of intangible and other assets	71	291
Stock-based compensation	3,492	2,646
Other	4,597	3,502
Cash provided (used) by changes in assets and liabilities:
Accounts receivable	(1,531)	24,937
Inventories	6,098	8,171
Prepaid insurance	8,693	10,346
Supplies, prepaid items and other	(1,481)	2,192
Accounts payable	(5,587)	(14,789)
Accrued interest	(3,749)	(4,054)
Other assets and other liabilities	(1,091)	(4,127)
Net cash provided by operating activities	65,489	102,949
Cash flows from investing activities
Expenditures for property, plant and equipment	(33,047)	(32,263)
Proceeds from short-term investments	236,493	264,212
Purchases of short-term investments	(34,689)	(201,751)
Other investing activities	29	10
Net cash provided by investing activities	168,786	30,208
Cash flows from financing activities
Repurchases of 6.25% Senior Secured Notes	(92,216)	(114,320)
Payments on other long-term debt	(2,925)	(6,800)
Payments on short-term financing	(8,847)	(11,016)
Acquisition of treasury stock, net	(14,208)	(19,718)
Payments of debt-related costs	(777)
Net cash used by financing activities	(118,973)	(151,854)
Net increase (decrease) in cash and cash equivalents	115,302	(18,697)
Cash, cash equivalents and restricted cash at beginning of period	101,032	63,769
Cash, cash equivalents and restricted cash at end of period	$ 216,334	$ 45,072