Chapter 11 Proceedings - Debtor-in-Possession Condensed Combined Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 422,701		$ 156,281
Accounts receivable	144,257		256,315
Less: allowance for credit losses	(5,633)		(5,459)
Accounts receivable, net	138,624		250,856
Prepaid expenses and other current assets	63,269		68,658
Assets held for sale	2,000		1,000
Total current assets	652,286		476,795
Drilling and other property and equipment, net of accumulated depreciation	4,243,106		5,152,828
Other assets	206,481		204,421
Total assets	5,101,873		5,834,044
Current liabilities:
Accounts payable	31,980		68,586
Accrued liabilities	127,516		210,780
Taxes payable	28,359		23,228
Total current liabilities	187,855		302,594
Long-term debt			1,975,741
Deferred tax liability	30,614		47,528
Other liabilities	97,645		275,971
Commitments and contingencies (Note 10)
Total liabilities not subject to compromise	316,114		2,601,834
Liabilities subject to compromise	2,653,655
Stockholders’ equity:
Preferred stock (par value $0.01, 25,000,000 shares authorized, none issued and outstanding)
Common stock (par value $0.01, 500,000,000 shares authorized; 145,263,865 shares issued and 138,054,311 shares outstanding at September 30, 2020; 144,781,766 shares issued and 137,703,910 shares outstanding at December 31, 2019)	1,453		1,448
Additional paid-in capital	2,029,979		2,024,347
Retained earnings	306,835		1,412,201
Accumulated other comprehensive loss			(18)
Treasury stock, at cost (7,209,554 and 7,077,856 shares of common stock at September 30, 2020 and December 31, 2019, respectively)	(206,163)		(205,768)
Total stockholders’ equity	2,132,104	$ 2,230,689	3,232,210	$ 3,305,324	$ 3,398,897	$ 3,584,653
Total liabilities and stockholders’ equity	5,101,873		$ 5,834,044
Debtor [Member]
Current assets:
Cash and cash equivalents	407,222
Restricted cash	25,692
Accounts receivable	128,480
Less: allowance for credit losses	(175)
Accounts receivable, net	128,305
Prepaid expenses and other current assets	49,577
Assets held for sale	1,000
Total current assets	611,796
Drilling and other property and equipment, net of accumulated depreciation	4,232,543
Investments in non-debtor subsidiaries	2,458,447
Noncurrent deferred tax assets, net	31,356
Other assets	192,094
Total assets	7,526,236
Current liabilities:
Accounts payable	28,993
Accrued liabilities	114,935
Taxes payable	26,062
Amounts payable to non-debtor subsidiaries	1,043,326
Total current liabilities	1,213,316
Note payable to non-debtor subsidiary	328,000
Other liabilities	45,157
Commitments and contingencies (Note 10)
Total liabilities not subject to compromise	1,586,473
Liabilities subject to compromise	2,653,655
Stockholders’ equity:
Total stockholders’ equity	3,286,108
Total liabilities and stockholders’ equity	$ 7,526,236