CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 64,425	$ 91,196
Accounts receivable, net	44,937	33,527
Due from related parties	108	0
Inventories, net (Notes 6 and 13)	16,961	70,040
Income tax receivable	7,944	15,808
Other prepaid and deferred charges	25,798	27,527
Other assets	6,810	4,205
Total current assets	166,983	242,303
Noncurrent assets
Property, plant, and equipment, net (Note 6)	68,468	654,372
Income tax receivable	7,884	15,768
Other assets	31,476	16,213
Total assets	274,811	928,656
Current liabilities
Accounts payable	31,780	34,210
Royalties and production and property taxes (Note19)	13,974	53,232
Accrued expenses	14,610	26,385
Due to related parties	0	71
Current portion of federal coal lease obligations (Notes 15 and 19)	0	379
Debtor-in-possession financing	11,313	0
Other liabilities	1,556	4,019
Total current liabilities	73,233	118,296
Noncurrent liabilities
Senior notes (Notes 14 and 19)		396,373
Federal coal lease obligations, net of current portion (Notes 15 and 19)	0	1,404
Asset retirement obligations, net of current portion	100,939	92,591
Royalties and production and property taxes (Note 19)	3,124	20,587
Other liabilities	181	5,731
Total liabilities not subject to compromise	177,477	634,982
Liabilities subject to compromise
Liabilities subjec to compromise (Note 19)	464,369	0
Total liabilities	641,846	634,982
Equity
Common stock ($0.01 par value; 200,000 shares authorized; 76,985 and 76,283 shares issued and 76,508 and 75,806 outstanding as of June 30, 2019 and December 31, 2017, respectively)	765	758
Treasury stock, at costs (477 shares as of both June 30, 2019 and December 31, 2018)	(6,498)	(6,498)
Additional paid-in capital	658,899	656,925
Retained earnings (accumulated deficit)	(1,029,975)	(370,795)
Accumulated other comprehensive income (loss)	9,774	13,284
Total equity	(367,035)	293,674
Total liabilities and equity	$ 274,811	$ 928,656