CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Consolidated Statements of Operations
Revenues	$ 358,516	$ 467,926	$ 693,172	$ 904,260
Cost of revenues (exclusive of items shown below)	265,088	312,079	517,483	607,684
Selling, general and administrative expenses	43,293	42,534	88,714	86,348
Depreciation and amortization	42,881	40,094	85,386	77,574
Gain on disposition of assets, net	(1,133)	(1,810)	(4,637)	(3,173)
Operating income	8,387	75,029	6,226	135,827
Interest expense	(164)	(113)	(253)	(218)
Interest income	594	458	1,394	860
Other (expense) income, net	(53)	4,104	392	9,499
Income before income taxes	8,764	79,478	7,759	145,968
Income tax provision	2,593	19,535	2,327	33,895
Net income	$ 6,171	$ 59,943	$ 5,432	$ 112,073
Earnings per share
Basic (in dollars per share)	$ 0.03	$ 0.28	$ 0.02	$ 0.52
Diluted (in dollars per share)	0.03	0.28	0.02	0.52
Dividends per share (in dollars per share)	$ 0.05	$ 0.10	$ 0.15	$ 0.20