Condensed Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Condensed Consolidated Income Statements
Revenues	$ 1,133,358	$ 450,389	$ 2,001,294	$ 807,932
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	639,760	355,329	1,147,985	665,235
Depreciation, depletion and amortization	32,780	27,884	64,990	53,681
Accretion on asset retirement obligations	4,430	5,437	8,860	10,874
Change in fair value of coal derivatives and coal trading activities, net	1,877	8,762	17,396	9,290
Selling, general and administrative expenses	26,516	24,119	53,164	45,599
Other operating expense (income), net	5,238	(4,347)	1,799	(9,615)
Costs, expenses and other operating	710,601	417,184	1,294,194	775,064
Income from operations	422,757	33,205	707,100	32,868
Interest expense, net
Interest expense	(5,138)	(2,941)	(12,185)	(7,069)
Interest and investment income	528	147	552	474
Interest expense, net	(4,610)	(2,794)	(11,633)	(6,595)
Income before nonoperating expenses	418,147	30,411	695,467	26,273
Nonoperating expenses
Non-service related pension and postretirement benefit costs	(459)	(539)	(1,332)	(2,066)
Net loss resulting from early retirement of debt	(9,629)		(13,749)
Nonoperating expenses	(10,088)	(539)	(15,081)	(2,066)
Income before income taxes	408,059	29,872	680,386	24,207
Provision for income taxes	496	2,006	951	2,383
Net income	$ 407,563	$ 27,866	$ 679,435	$ 21,824
Net income per common share
Basic earnings per share (in dollars per share)	$ 24.26	$ 1.82	$ 42.14	$ 1.43
Diluted earnings per share (in dollars per share)	$ 19.30	$ 1.66	$ 32.21	$ 1.31
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	16,801	15,294	16,124	15,289
Diluted weighted average shares outstanding (in shares)	21,452	16,756	21,362	16,598
Dividends declared per common share (in dollars per share)	$ 8.11		$ 8.36