Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Statement Of Financial Position [Abstract]
Property and equipment, accumulated depreciation (in dollars)	$ 800,715	$ 767,403
Intangible assets, excluding goodwill, accumulated amortization (in dollars)	$ 40,528	$ 38,957
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, Authorized shares	500,000,000	500,000,000
Common stock, shares issued	107,003,000	113,138,000
Common stock, shares outstanding	106,930,000	112,913,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, Authorized shares	50,000,000	50,000,000
Preferred stock, shares issued	0	0