Parent Guarantor - Schedule of Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets:
Cash and cash equivalents	$ 44,658	$ 32,774			$ 224,692	$ 314,466
Accounts receivable, net of allowance for doubtful accounts	57,473	72,943
Other current assets	4,914	84,064
Property and equipment, net	2,096,160	2,029,523
Investment in subsidiaries	0	0
Noncurrent assets	9,331	33,156
Total	2,212,536	2,252,460
Liabilities and Stockholders' Equity:
Accounts payable and other accrued liabilities	135,762	131,379
Other current liabilities	113,993	116,806
Long-term debt, net of debt issuance costs	687,768	617,387
Deferred income taxes	109,823	139,534
Other noncurrent liabilities	48,715	35,256
Stockholders' equity	1,116,475	1,212,098	$ 987,797	$ 1,015,203	1,060,340	598,554
Total liabilities and stockholders' equity	2,212,536	2,252,460
Intercompany Eliminations
Assets:
Cash and cash equivalents	0	0			0	0
Accounts receivable, net of allowance for doubtful accounts	0	0
Other current assets	0	0
Property and equipment, net	0	0
Investment in subsidiaries	(1,116,475)	(1,212,098)
Noncurrent assets	0	0
Total	(1,116,475)	(1,212,098)
Liabilities and Stockholders' Equity:
Accounts payable and other accrued liabilities	0	0
Other current liabilities	0	0
Long-term debt, net of debt issuance costs	0	0
Deferred income taxes	0	0
Other noncurrent liabilities	0	0
Stockholders' equity	(1,116,475)	(1,212,098)
Total liabilities and stockholders' equity	(1,116,475)	(1,212,098)
Parent Guarantor | Reportable Legal Entities
Assets:
Cash and cash equivalents	0	0			0	0
Accounts receivable, net of allowance for doubtful accounts	0	0
Other current assets	0	0
Property and equipment, net	0	0
Investment in subsidiaries	1,116,475	1,212,098
Noncurrent assets	0	0
Total	1,116,475	1,212,098
Liabilities and Stockholders' Equity:
Accounts payable and other accrued liabilities	0	0
Other current liabilities	0	0
Long-term debt, net of debt issuance costs	0	0
Deferred income taxes	0	0
Other noncurrent liabilities	0	0
Stockholders' equity	1,116,475	1,212,098
Total liabilities and stockholders' equity	1,116,475	1,212,098
Subsidiary Issuer | Reportable Legal Entities
Assets:
Cash and cash equivalents	44,658	32,774			$ 224,692	$ 314,466
Accounts receivable, net of allowance for doubtful accounts	57,473	72,943
Other current assets	4,914	84,064
Property and equipment, net	2,096,160	2,029,523
Investment in subsidiaries	0	0
Noncurrent assets	9,331	33,156
Total	2,212,536	2,252,460
Liabilities and Stockholders' Equity:
Accounts payable and other accrued liabilities	135,762	131,379
Other current liabilities	113,993	116,806
Long-term debt, net of debt issuance costs	687,768	617,387
Deferred income taxes	109,823	139,534
Other noncurrent liabilities	48,715	35,256
Stockholders' equity	1,116,475	1,212,098
Total liabilities and stockholders' equity	$ 2,212,536	$ 2,252,460