Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net income (loss)	$ 1,330,914	$ 337,573	$ (344,615)
Adjustments to reconcile to cash from operating activities:
Depreciation, depletion and amortization	133,300	120,327	121,552
Accretion on asset retirement obligations	17,721	21,748	19,887
Deferred income taxes	(222,023)	8	14,430
Employee stock-based compensation expense	27,383	20,539	17,435
Amortization relating to financing activities	2,459	6,549	5,599
Gain on property insurance recovery related to Mountain Laurel longwall			(23,518)
Gain on disposals and divestitures, net	(997)	23,276	(3,727)
Reclamation work completed	(13,720)	(39,047)	(14,357)
Contribution to fund for asset retirement obligations	(115,993)	(20,000)
Non-cash asset impairment and restructuring			198,007
Changes in:
Receivables	77,274	(212,950)	63,657
Inventories	(66,281)	(30,726)	(9,126)
Accounts payable, accrued expenses and other current liabilities	84,947	45,547	(46,066)
Income taxes, net	(30,507)	1,820	22,859
Coal derivative assets and liabilities, including margin account	1,274	(3,553)	(1,045)
Asset retirement obligations	(1,193)	(13,697)	(1,787)
Pension, postretirement and other postemployment benefits	(25,537)	4,571	588
Other	10,519	(23,701)	41,333
Cash provided by operating activities	1,209,540	238,284	61,106
Investing activities
Capital expenditures	(172,728)	(245,440)	(285,821)
Minimum royalty payments	(1,069)	(1,186)	(1,248)
Proceeds from disposals and divestitures	1,972	21,228	1,007
Purchases of short-term investments	(39,731)		(120,624)
Proceeds from sales of short-term investments	17,337	87,486	158,708
Investments in and advances to affiliates, net	(9,575)	(3,303)	(1,549)
Proceeds from property insurance recovery related to Mountain Laurel longwall			23,518
Cash used in investing activities	(203,794)	(141,215)	(226,009)
Financing activities
Payments on term loan due 2024	(273,788)	(7,895)	(3,000)
Proceeds from equipment financing		19,438	53,611
Proceeds from tax exempt bonds		44,985	53,090
Payments on convertible debt	(208,130)
Proceeds from convertible debt			155,250
Purchase of capped call related to convertible debt			(17,543)
Net payments on other debt	(11,235)	(11,195)	(15,922)
Debt financing costs	(1,035)	(2,057)	(9,718)
Dividends paid	(456,392)	(3,830)	(8,245)
Purchases of treasury stock	(156,790)
Payments for taxes related to net share settlement of equity awards	(7,052)	(4,840)	(2,195)
Proceeds from warrants exercised	19,540	1,175
Cash (used in) provided by financing activities	(1,094,882)	35,781	205,328
Increase (decrease) in cash and cash equivalents, including restricted cash	(89,136)	132,850	40,425
Cash and cash equivalents, including restricted cash, beginning of period	326,295	193,445	153,020
Cash and cash equivalents, including restricted cash, end of period	237,159	326,295	193,445
SUPPLEMENTAL CASH FLOW INFORMATION
Cash and cash equivalents	236,059	325,194	187,492
Restricted Cash	1,100	1,101	5,953
Cash paid during the period for interest	$ 18,820	$ 31,568	19,602
Cash refunded during the period for income taxes, net			$ 37,535