Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Current assets:
Cash and cash equivalents - unrestricted	$ 12,122	$ 135,946	$ 124,398	$ 180,029
Cash and cash equivalents - restricted	1,150		1,150
Trade receivables, less allowance of $ 755 and $ 882, respectively	49,871		31,793
Estimated fair value of derivative assets	0		22
Deferred income taxes	5,544		6,495
Other current assets	59,123		48,992
Total current assets	127,810		212,850
Property and equipment, net of accumulated depreciation	2,200,192		2,201,445
Notes receivable, net of current portion	141,742		142,651
Long-term deferred financing costs	17,169		12,521
Other long-term assets	51,428		51,065
Long-term assets of discontinued operations	401		401
Total assets	2,538,742		2,620,933
Current liabilities:
Current portion of long-term debt and capital lease obligations	746		58,574
Accounts payable and accrued liabilities	161,355		175,343
Estimated fair value of derivative liabilities	345		12,475
Current liabilities of discontinued operations	281		357
Total current liabilities	162,727		246,749
Long-term debt and capital lease obligations, net of current portion	1,069,956		1,100,641
Deferred income taxes	110,902		101,140
Other long-term liabilities	141,751		142,200
Long-term liabilities of discontinued operations	451		451
Commitments and contingencies
Stockholders' equity:
Preferred stock, $.01 par value, 100,000 shares authorized, no shares issued or outstanding
Common stock, $.01 par value, 150,000 shares authorized, 48,403 and 48,144 shares issued and outstanding, respectively	484		481
Additional paid-in capital	926,668		916,359
Treasury stock of 385 shares, at cost	(4,599)		(4,599)
Retained earnings	150,674		145,600
Accumulated other comprehensive loss	(20,272)		(28,089)
Total stockholders' equity	1,052,955		1,029,752
Total liabilities and stockholders' equity	$ 2,538,742		$ 2,620,933