CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CONSOLIDATED STATEMENTS OF OPERATIONS
REVENUES	$ 598,302	$ 1,222,409	$ 1,721,005
Cost of revenues (exclusive of items shown separately below)	480,739	919,595	1,183,048
Selling, general and administrative expenses	123,698	168,127	168,151
Impairment and other charges	217,493	82,273
Depreciation and amortization	95,530	170,409	163,120
Gain on disposition of assets, net	(9,523)	(3,707)	(3,344)
Operating (loss) profit	(309,635)	(114,288)	210,030
Interest expense	(373)	(334)	(489)
Interest income	496	1,906	2,426
Other income (expense) , net	81	(385)	9,313
(Loss) income before income taxes	(309,431)	(113,101)	221,280
Income tax (benefit) provision	(97,239)	(25,990)	45,878
Net (loss) income	$ (212,192)	$ (87,111)	$ 175,402
(LOSS) EARNINGS PER SHARE
Basic (in dollars per share)	$ (1.00)	$ (0.41)	$ 0.82
Diluted (in dollars per share)	$ (1.00)	(0.41)	0.82
Dividend per share (in dollars per share)		$ 0.15	$ 0.47