Consolidated Statements of Cash Flow - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Cash flows from operating activities:
Net Income (Loss) Available to Common Stockholders, Basic	$ 394,261	$ 270,360	$ 219,783
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization, including debt cost	57,441	49,643	48,893
Allowance for doubtful accounts	187	1,175	(578)
Impairment of long-lived assets	19,365	0	0
Equity in losses of unconsolidated affiliates	671	895	0
Stock-based payment compensation	20,840	20,864	18,154
Excess tax benefit from stock-based payment compensation	0	0	(2,971)
Loss (gain) on sale of property and equipment	184	(54)	(918)
Deferred income taxes	19,901	5,740	4,365
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	(38,542)	(54,213)	(20,417)
Vehicle pooling costs	(1,915)	(4,137)	(891)
Inventories	1,294	(2,509)	(1,731)
Prepaid expenses and other current assets	1,760	(738)	69
Other assets	1,085	4,164	10,125
Accounts payable and accrued liabilities	4,269	48,347	(3,926)
Deferred revenue	392	983	(438)
Income taxes receivable	12,343	(12,649)	(806)
Income taxes payable	(333)	2,788	(1,971)
Other liabilities	(1,145)	1,839	(1,666)
Net cash provided by operating activities	492,058	332,498	265,076
Cash flows from investing activities:
Purchases of property and equipment	(172,178)	(173,917)	(79,153)
Proceeds from sale of property and equipment	660	562	1,521
Proceeds from sale of assets held for sale	105	100	217
Investment in unconsolidated affiliate	(3,566)	0	(4,500)
Purchases of assets and liabilities in connection with acquisitions, net of cash acquired	(160,812)	0	0
Purchases of marketable securities	0	(21,119)	0
Proceeds from sale of marketable securities	0	21,498	0
Net cash used in investing activities	(335,791)	(172,876)	(81,915)
Goodwill impairment losses	21,800	21,800
Cash flows from financing activities:
Proceeds from the exercise of stock options	31,188	13,240	3,634
Excess tax benefit from stock-based payment compensation	0	0	2,971
Proceeds from the issuance of Employee Stock Purchase Plan shares	4,270	3,369	3,079
Repurchases of common stock	0	(442,855)	(233,484)
Payments for employee stock-based tax withholdings	(135,433)	(15,039)	(3,822)
Proceeds from the issuance of long-term debt, net of discount	0	93,468	698,939
Net (repayments) proceeds on revolving loan facility	(7,000)	238,000	0
Debt offering costs	0	(1,179)	(955)
Principal payments on long-term debt	0	(337,500)	(350,000)
Net cash (used in) provided by financing activities	(106,975)	(448,496)	120,362
Effect of foreign currency translation	4,959	(11,289)	(6,179)
Net increase (decrease) in cash and cash equivalents	54,251	(300,163)	297,344
Cash and cash equivalents at beginning of period	155,849	456,012	158,668
Cash and cash equivalents at end of period	210,100	155,849	456,012
Supplemental disclosure of cash flow information:
Interest paid	23,221	23,606	18,121
Income taxes paid, net of refunds	$ 14,011	$ 127,981	$ 109,925