Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Total revenues	$ 216,706	$ 268,861	$ 450,248	$ 564,371
Operating expenses:
Depreciation	88,253	81,825	175,151	163,650
General and administrative	15,294	18,236	32,605	36,749
Impairment of assets		27,225		27,225
Restructuring and separation costs		1,265		4,276
Gain on disposition of assets	(9,436)	(50)	(5,149)	(560)
Total operating expenses	328,206	321,236	610,874	616,234
Operating loss	(111,500)	(52,375)	(160,626)	(51,863)
Other income (expense):
Interest income	1,933	2,001	4,346	3,638
Interest expense, net of amounts capitalized	(31,159)	(29,585)	(61,084)	(57,903)
Foreign currency transaction (loss) gain	(721)	411	(1,806)	858
Other, net	105	262	438	842
Loss before income tax benefit	(141,342)	(79,286)	(218,732)	(104,428)
Income tax benefit	27,354	10,012	31,416	54,475
Net loss	$ (113,988)	$ (69,274)	$ (187,316)	$ (49,953)
Loss per share, Basic and Diluted	$ (0.83)	$ (0.50)	$ (1.36)	$ (0.36)
Weighted-average shares outstanding:
Shares of common stock	137,691	137,429	137,607	137,362
Total weighted-average shares outstanding	137,691	137,429	137,607	137,362
Contract Drilling [Member]
Revenues:
Total revenues	$ 207,273	$ 265,353	$ 433,970	$ 553,279
Operating expenses:
Contract drilling, excluding depreciation	224,782	189,321	392,210	374,010
Reimbursable Expenses [Member]
Revenues:
Total revenues	9,433	3,508	16,278	11,092
Operating expenses:
Contract drilling, excluding depreciation	$ 9,313	$ 3,414	$ 16,057	$ 10,884