Effect of Error on the Consolidated Balance Sheet (Detail) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Dec. 31, 2009
Property and equipment, net	$ 16,988,832	$ 16,771,677	$ 15,268,437
Other assets	1,197,307	1,107,753	1,137,224
Total assets	20,170,026	19,653,829	18,224,425
Accrued expenses and other liabilities	526,158	553,218	522,057
Total current liabilities	3,115,241	3,445,173	2,749,897
Retained earnings	5,809,150	5,259,998	4,745,014
Total shareholders' equity	8,438,096	7,900,752	7,489,781
Total liabilities and shareholders' equity	20,170,026	19,653,829	18,224,425
As Previously Reported
Property and equipment, net		16,769,181	15,268,053
Other assets		1,151,324	1,146,677
Total assets		19,694,904	18,233,494
Accrued expenses and other liabilities		552,543	521,190
Total current liabilities		3,444,498	2,749,030
Retained earnings		5,301,748	4,754,950
Total shareholders' equity		7,942,502	7,499,717
Total liabilities and shareholders' equity		19,694,904	18,233,494
Adjustment
Property and equipment, net		2,496	384
Other assets		(43,571)	(9,453)
Total assets		(41,075)	(9,069)
Accrued expenses and other liabilities		675	867
Total current liabilities		675	867
Retained earnings		(41,750)	(9,936)
Total shareholders' equity		(41,750)	(9,936)
Total liabilities and shareholders' equity		$ (41,075)	$ (9,069)