Condensed Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues	$ 319,521	$ 570,222	$ 724,753	$ 1,125,405
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	316,348	451,088	691,347	889,559
Depreciation, depletion and amortization	30,167	26,535	61,475	51,873
Accretion on asset retirement obligations	4,986	5,137	9,992	10,274
Change in fair value of coal derivatives and coal trading activities, net	(129)	(8,400)	614	(21,381)
Selling, general and administrative expenses	19,738	25,209	42,483	49,298
Costs related to proposed joint venture with Peabody Energy	7,851	3,018	11,515	3,018
Severance costs related to voluntary separation plan	7,437		13,265
Gain on property insurance recovery related to Mountain Laurel longwall	(14,518)		(23,518)
Other operating income, net	(5,704)	(3,239)	(11,874)	(4,889)
Costs, expenses and other operating	364,807	503,652	793,930	982,056
Income (loss) from operations	(45,286)	66,570	(69,177)	143,349
Interest expense, net
Interest expense	(3,523)	(4,375)	(6,911)	(8,807)
Interest and investment income	1,793	2,088	3,052	4,231
Interest expense, net	(1,730)	(2,287)	(3,859)	(4,576)
Income (loss) before nonoperating expenses	(47,016)	64,283	(73,036)	138,773
Nonoperating (expenses) income
Non-service related pension and postretirement benefit costs	(1,102)	(1,336)	(2,198)	(3,102)
Reorganization items, net		(16)	26	71
Nonoperating (expenses) income	(1,102)	(1,352)	(2,172)	(3,031)
Income (loss) before income taxes	(48,118)	62,931	(75,208)	135,742
Provision for (benefit from) income taxes	1,206	91	(585)	161
Net income (loss)	$ (49,324)	$ 62,840	$ (74,623)	$ 135,581
Net income (loss) per common share
Basic earnings per common share (in dollars per share)	$ (3.26)	$ 3.80	$ (4.93)	$ 7.97
Diluted earnings per common share (in dollars per share)	$ (3.26)	$ 3.53	$ (4.93)	$ 7.45
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	15,145	16,543	15,142	17,018
Diluted weighted average shares outstanding (in shares)	15,145	17,781	15,142	18,190
Dividends declared per common share (in dollars per share)		$ 0.45	$ 0.50	$ 0.90
Dal-Tex and Briar Branch Properties
Costs, expenses and other operating
(Gain) loss on divestitures	$ (1,369)	$ 4,304	$ (1,369)	$ 4,304