Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data	Sep. 30, 2011	Sep. 30, 2010
Consolidated Balance Sheets
Trade accounts receivable, allowance for doubtful accounts (in dollars)	$ 2,086	$ 2,756
Property and equipment, accumulated depreciation (in dollars)	317,677	291,186
Intangible assets, excluding goodwill, accumulated amortization (in dollars)	$ 45,467	$ 33,031
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, Authorized shares	500,000	500,000
Common stock, shares issued	184,502	182,592
Common stock, shares outstanding	184,057	182,230
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, Authorized shares	50,000	50,000
Preferred stock, shares issued	0	0
Treasury stock, shares	15	15