Condensed Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	6 Months Ended
	Nov. 30, 2012	Nov. 30, 2011
Cash flows from operating activities:
Net income attributable to AAR and noncontrolling interest	$ 36.2	$ 34.2
Adjustments to reconcile net income attributable to AAR and noncontrolling interest to net cash provided from operating activities:
Depreciation and amortization	40.6	32.7
Amortization of stock-based compensation	4.8	6.1
Amortization of debt discount	5.7	6.5
Amortization of overhaul costs	12.7	2.2
Deferred tax provision	9.7	5.6
Earnings from joint ventures	(2.6)	(0.5)
Changes in certain assets and liabilities:
Accounts and notes receivable	19.2	0.5
Inventories	(20.8)	(60.2)
Rotable spares and equipment on or available for short-term lease	5.1	0.4
Equipment on long-term lease	1.3	24.1
Accounts and trade notes payable	(28.9)	20.9
Accrued and other liabilities	2.2	(7.8)
Other, primarily program and overhaul costs	(24.9)	(59.9)
Net cash provided from operating activities	60.3	4.8
Cash flows used in investing activities:
Property, plant and equipment expenditures	(19.1)	(55.2)
Proceeds from sale of equipment	11.5
Payments for acquisitions	(16.5)	(19.5)
Other	(0.7)	0.4
Net cash used in investing activities	(24.8)	(74.3)
Cash flows (used in) provided from financing activities:
Proceeds from borrowing	20.0	63.2
Reduction in borrowing	(39.3)	(9.5)
Reduction in capital lease obligations		(6.7)
Reduction in equity due to convertible bond repurchases	(0.5)
Cash dividends	(7.1)	(6.1)
Purchase of treasury stock	(8.5)	(3.7)
Stock option exercises		2.9
Tax benefits from exercise of stock options		0.8
Other	0.1	(1.4)
Net cash (used in) provided from financing activities	(35.3)	39.5
Effect of exchange rate changes on cash	1.3	0.5
Increase (decrease) in cash and cash equivalents	1.5	(29.5)
Cash and cash equivalents, beginning of period	67.7	57.4
Cash and cash equivalents, end of period	$ 69.2	$ 27.9