Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$ 78,402	$ 74,393
Restricted cash	985
Accounts receivable, net of allowance	250,537	248,588
Current deferred tax assets	8,411	13,229
Prepaid expenses and other current assets	36,233	29,775
Total current assets	374,568	365,985
Property and equipment, net	2,772,743	2,658,628
Restricted cash	122	2,858
Investment in direct financing lease	1,348	3,223
Goodwill	15,155	16,110
Non-current deferred tax assets	5,876	2,301
Other assets	80,820	78,086
Total assets	3,250,632	3,127,191
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	322,271	317,566
Income taxes payable	1,483	1,368
Current liabilities of discontinued operations		54
Total current liabilities	323,754	318,988
Long-term debt	1,320,000	1,200,000
Deferred revenue	72,722	87,227
Other liabilities	60,275	39,476
Total liabilities	1,776,751	1,645,691
Total stockholders' equity	1,473,881	1,481,500	$ 1,502,293	$ 1,502,507
Total liabilities and stockholders' equity	3,250,632	3,127,191
Parent
ASSETS
Cash and cash equivalents	32,417	12,337
Restricted cash	645
Accounts receivable, net of allowance	173,613	167,626
Current deferred tax assets	164
Prepaid expenses and other current assets	3,512	17,060
Total current assets	210,351	197,023
Property and equipment, net	2,531,397	2,459,053
Restricted cash	122	1,267
Investment in direct financing lease	1,348	3,223
Other assets	252,542	241,690
Total assets	2,995,760	2,902,256
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	200,169	218,403
Income taxes payable	3	195
Current deferred tax liabilities		13
Total current liabilities	200,172	218,611
Long-term debt	1,320,000	1,200,000
Non-current deferred tax liabilities	354	477
Other liabilities	1,353	1,668
Total liabilities	1,521,879	1,420,756
Total stockholders' equity	1,473,881	1,481,500
Total liabilities and stockholders' equity	2,995,760	2,902,256
Combined Subsidiary Guarantors
ASSETS
Cash and cash equivalents	45,985	62,056
Restricted cash	340
Accounts receivable, net of allowance	154,382	178,911
Current deferred tax assets	8,247	13,241
Prepaid expenses and other current assets	40,680	34,705
Total current assets	249,634	288,913
Property and equipment, net	241,346	199,575
Restricted cash		1,591
Goodwill	15,155	16,110
Non-current deferred tax assets	6,230	2,778
Other assets	45,657	47,046
Total assets	558,022	556,013
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	207,484	205,213
Income taxes payable	1,480	1,173
Note payable to an affiliate		13,854
Current liabilities of discontinued operations		54
Total current liabilities	208,964	220,294
Long-term debt	115,000	115,000
Deferred revenue	72,722	87,227
Other liabilities	58,922	37,808
Total liabilities	455,608	460,329
Total stockholders' equity	102,414	95,684
Total liabilities and stockholders' equity	558,022	556,013
Consolidating Adjustments and Other
ASSETS
Accounts receivable, net of allowance	(77,458)	(97,949)
Current deferred tax assets		(12)
Prepaid expenses and other current assets	(7,959)	(21,990)
Total current assets	(85,417)	(119,951)
Non-current deferred tax assets	(354)	(477)
Other assets	(217,379)	(210,650)
Total assets	(303,150)	(331,078)
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable and accrued expenses	(85,382)	(106,050)
Current deferred tax liabilities		(13)
Note payable to an affiliate		(13,854)
Total current liabilities	(85,382)	(119,917)
Long-term debt	(115,000)	(115,000)
Non-current deferred tax liabilities	(354)	(477)
Total liabilities	(200,736)	(235,394)
Total stockholders' equity	(102,414)	(95,684)
Total liabilities and stockholders' equity	$ (303,150)	$ (331,078)