Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	May 31, 2014	May 31, 2013
Cash flows from operating activities:
Net income	$ 29,091	$ 24,503
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	31,087	30,447
Stock-based compensation expense	2,784	2,812
Other	(3,195)	(53)
(Increase) decrease in operating assets:
Restricted cash	1,979	1,112
Accounts receivable and other assets	(4,168)	(209)
Increase (decrease) in operating liabilities:
Accounts payable	(1,435)	2,102
Accrued and other liabilities	4,317	2,797
Income taxes	10,598	(7,661)
Total adjustments	41,967	31,347
Net cash provided by operating activities	71,058	55,850
Cash flows from investing activities:
Purchases of property and equipment	(54,738)	(28,378)
Proceeds from sale of assets	1,653	32,342
Other	(415)	140
Net cash provided by (used in) investing activities	(53,500)	4,104
Cash flows from financing activities:
Payments on debt	(7,340)	(31,076)
Purchases of treasury stock	(68,884)	(36,538)
Proceeds from exercise of stock options	16,700	11,181
Other	(1,090)	(2,614)
Net cash used in financing activities	(60,614)	(59,047)
Net increase (decrease) in cash and cash equivalents	(43,056)	907
Cash and cash equivalents at beginning of period	77,896	52,647
Cash and cash equivalents at end of period	34,840	53,554
Cash paid during the period for:
Income taxes (net of refunds)	4,826	21,074
Non-cash investing and financing activities:
Change in obligation to acquire treasury stock	571	(1,058)
Notes receivable and direct financing leases from property disposition		$ 8,661