CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net loss	$ (155,723)	$ (156,369)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, amortization and impairment	375,545	347,745
Dry holes and abandonments	28
Deferred income tax benefit	(90,684)	(58,643)
Stock-based compensation expense	22,170	14,192
Net gain on asset disposals	(15,367)	(7,267)
Tax expense on stock-based compensation		(2,995)
Amortization of debt issuance costs	173	723
Changes in operating assets and liabilities:
Accounts receivable	(135,542)	91,559
Income taxes receivable	(1,141)	(2,329)
Inventory and other assets	(29,186)	3,795
Accounts payable	58,372	(25,738)
Accrued expenses	(13,002)	(21,658)
Other liabilities	(258)	(1,088)
Net cash provided by operating activities	15,385	181,927
Cash flows from investing activities:
Acquisition, net of cash acquired	(434,194)
Purchases of property and equipment	(186,790)	(51,834)
Proceeds from disposal of assets	34,997	12,350
Net cash used in investing activities	(585,987)	(39,484)
Cash flows from financing activities:
Proceeds from equity offering	471,570
Purchases of treasury stock	(3,727)	(3,611)
Dividends paid	(7,595)	(17,665)
Repayment of long-term debt		(25,000)
Proceeds from borrowings under revolving credit facility	161,000
Repayment of borrowings under revolving credit facility	(46,000)
Net cash provided by (used in) financing activities	575,248	(46,276)
Effect of foreign exchange rate changes on cash	334	114
Net increase in cash and cash equivalents	4,980	96,281
Cash and cash equivalents at beginning of period	35,152	113,346
Cash and cash equivalents at end of period	40,132	209,627
Net cash (paid) received during the period for:
Interest, net of capitalized interest of $409 in 2017 and $286 in 2016	(16,640)	(20,252)
Income taxes	967	19,603
Non-cash investing and financing activities:
Net increase in payables for purchases of property and equipment	33,938	9,283
Issuance of common stock for business acquisition	1,039,396
Net decrease in deposits on equipment purchases	$ 3,133	$ 4,397