Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 2,294,352	$ 2,451,787	$ 2,324,623
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	1,873,017	1,925,202	1,839,993
Depreciation, depletion and amortization	112,055	119,563	122,464
Accretion on asset retirement obligations	20,548	27,970	30,209
Amortization of sales contracts, net	(434)	11,107	53,985
Change in fair value of coal derivatives and coal trading activities, net	(18,601)	9,118	7,222
Selling, general and administrative expenses	95,781	100,300	87,952
Costs related to proposed joint venture with Peabody Energy	13,816	0	0
Preference Rights Lease Application settlement income	(39,000)	0	0
Other operating income, net	(19,012)	(20,611)	(30,241)
Costs, expenses and other operating	2,051,482	2,172,649	2,090,287
Income from operations	242,870	279,138	234,336
Interest expense, net
Interest expense	(16,485)	(20,471)	(26,905)
Interest and investment income	9,691	6,782	2,649
Interest expense, net	(6,794)	(13,689)	(24,256)
Income before nonoperating expenses	236,076	265,449	210,080
Nonoperating income (expense)
Non-service related pension and postretirement benefit costs	(2,053)	(3,202)	(1,940)
Net loss resulting from early retirement of debt and debt restructuring	0	(485)	(2,547)
Reorganization income (loss), net	24	(1,661)	(2,398)
Nonoperating income (expense)	(2,029)	(5,348)	(6,885)
Income before income taxes	234,047	260,101	203,195
Provision for (benefit from) income taxes	248	(52,476)	(35,255)
Net income	$ 233,799	$ 312,577	$ 238,450
Earnings per common share
Basic earnings per common share (in dollars per share)	$ 14.42	$ 15.90	$ 10.05
Diluted earnings per common share (in dollars per share)	$ 13.52	$ 15.15	$ 9.84
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	16,218	19,663	23,725
Diluted weighted average shares outstanding (in shares)	17,298	20,629	24,240
Coal-Mac LLC
Costs, expenses and other operating
(Gain) loss on sale of disposal group	$ 9,008	$ 0	$ 0
Lone Mountain Processing, Inc.
Costs, expenses and other operating
(Gain) loss on sale of disposal group	$ 4,304	$ 0	$ (21,297)