AAR (AIR) 10-K 17 Jul 14 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	31-May-14	Jun. 30, 2014	Nov. 29, 2013
Document and Entity Information	'	'	'
Entity Registrant Name	'AAR CORP	'	'
Entity Central Index Key	'0000001750	'	'
Document Type	'10-K	'	'
Document Period End Date	31-May-14	'	'
Amendment Flag	'false	'	'
Current Fiscal Year End Date	'--05-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$1,169
Entity Common Stock, Shares Outstanding	'	39,590,411	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'FY	'	'

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	31-May-14	31-May-13	31-May-12
Sales:	'	'	'
Sales from products	$1,226.30	$1,228.50	$1,384.20
Sales from services	808.7	908.8	680.8
Total sales	2,035	2,137.30	2,065
Costs and operating expenses	'	'	'
Cost of products	1,068.40	1,115.50	1,208.60
Cost of services	626.4	707.6	534.1
Cost of sales - restructuring and impairment	'	'	3.7
Selling, general and administrative	197.6	198.4	189.4
Total costs and operating expenses	1,892.40	2,021.50	1,935.80
Earnings from joint ventures	3.1	6.8	1.5
Operating income	145.7	122.6	130.7
Loss on extinguishment of debt	'	-0.3	-0.7
Interest expense	-42	-41.6	-37.7
Interest income	1.6	1.5	1.2
Income before provision for income taxes	105.3	82.2	93.5
Provision for income taxes	32.1	26.7	25.5
Net income attributable to AAR and noncontrolling interest	73.2	55.5	68
Income attributable to noncontrolling interest	-0.3	-0.5	-0.3
Net income attributable to AAR	$72.90	$55	$67.70
Earnings per share - basic (in dollars per share)	$1.85	$1.38	$1.68
Earnings per share - diluted (in dollars per share)	$1.83	$1.38	$1.65

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME	'	'	'
Net income attributable to AAR and noncontrolling interest	$73.20	$55.50	$68
Other comprehensive income, net of tax:	'	'	'
Currency translation adjustments, net of tax	14	8.7	-18.5
Derivative instruments unrealized gain (loss), net of tax expense (benefit) of $0.4 in 2014, $0.3 in 2013, and ($2.1) in 2012	0.7	0.6	-3.9
Unrecognized pension and post retirement costs, net of tax expense (benefit) of ($0.8) in 2014, $1.8 in 2013, and ($7.6) in 2012	-1.5	3.4	-14.2
Total other comprehensive income, net of tax	13.2	12.7	-36.6
Comprehensive income	86.4	68.2	31.4
Less: Comprehensive income attributable to noncontrolling interests	-0.3	-0.5	-0.3
Comprehensive income attributable to AAR	$86.10	$67.70	$31.10

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME	'	'	'
Derivative instruments unrealized gain (loss), tax expense (benefit)	$0.40	$0.30	($2.10)
Unrecognized pension and post retirement costs, tax expense (benefit)	($0.80)	$1.80	($7.60)

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	31-May-14	31-May-13
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$89.20	$75.30
Accounts receivable	283.1	297.4
Inventories	495.3	453.7
Rotable spares and equipment on or available for short-term lease	137.6	129.2
Deposits, prepaids and other	81.6	60.1
Deferred tax assets	30.1	18
Total current assets	1,116.90	1,033.70
Property, plant and equipment, at cost:	'	'
Land	9.4	9.2
Buildings and improvements	102.4	99.5
Aircraft, equipment, furniture and fixtures	627.4	607.5
Property, plant and equipment, gross	739.2	716.2
Accumulated depreciation	-424.3	-354.5
Property, plant and equipment, net of accumulated depreciation	314.9	361.7
Other assets:	'	'
Goodwill	261.7	255.6
Intangible assets, net	165.4	157.8
Equipment on or available for long-term lease	98.4	64.7
Capitalized program development costs	112.2	124.9
Investment in joint ventures	29.9	31.8
Other	100.1	106.7
Total other assets	767.7	741.5
Total assets	2,199.50	2,136.90
Current liabilities:	'	'
Current maturities of long-term debt	69.7	86.4
Accounts and trade notes payable	171.1	149.3
Accrued liabilities	161.3	153.3
Total current liabilities	402.1	389
Long-term debt, less current maturities	564.3	622.2
Deferred tax liabilities	162.2	138.2
Other liabilities and deferred income	70.2	68
Total noncurrent liabilities	796.7	828.4
Equity:	'	'
Preferred stock, $1.00 par value, authorized 250,000 shares; none issued	'	'
Common stock, $1.00 par value, authorized 100,000,000 shares; issued 44,674,186 and 44,691,437 shares at cost, respectively	44.7	44.7
Capital surplus	436.4	431.6
Retained earnings	646	584.9
Treasury stock, 5,113,939 and 5,309,252 shares at cost, respectively	-98.3	-100.1
Accumulated other comprehensive loss	-29.3	-42.5
Total AAR stockholders' equity	999.5	918.6
Noncontrolling interest	1.2	0.9
Total equity	1,000.70	919.5
Total liabilities and equity	$2,199.50	$2,136.90

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	31-May-14	31-May-13
CONSOLIDATED BALANCE SHEETS	'	'
Preferred stock, par value (in dollars per share)	$1	$1
Preferred stock, authorized shares	250,000	250,000
Preferred stock, issued shares	0	0
Common stock, par value (in dollars per share)	$1	$1
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	44,674,186	44,691,437
Treasury stock, shares	5,113,939	5,309,252

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $)	Total	Total AAR Stockholders' Equity	Common Stock	Capital Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
In Millions, unless otherwise specified
Balance at May. 31, 2011	$835.30	$835.90	$45	$423.80	$486.10	($100.40)	($18.60)	($0.60)
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	68	67.7	'	'	67.7	'	'	0.3
Cash dividends	-12	-12	'	'	-12	'	'	'
Stock option activity	4.7	4.7	'	4.8	'	-0.1	'	'
Restricted stock activity	8.8	8.8	-0.2	-4.8	'	13.8	'	'
Repurchase of shares	-3.7	-3.7	'	'	'	-3.7	'	'
Equity portion of bond repurchase	-0.2	-0.2	'	-0.2	'	'	'	'
Other comprehensive income, net of tax	-36.6	-36.6	'	'	'	'	-36.6	'
Assumption of noncontrolling interest	1.7	'	'	'	'	'	'	1.7
Balance at May. 31, 2012	866	864.6	44.8	423.6	541.8	-90.4	-55.2	1.4
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	55.5	55	'	'	55	'	'	0.5
Cash dividends	-12.9	-11.9	'	'	-11.9	'	'	-1
Stock option activity	4.5	4.5	'	2.8	'	1.7	'	'
Restricted stock activity	7.8	7.8	-0.1	4.7	'	3.2	'	'
Repurchase of shares	-14.6	-14.6	'	'	'	-14.6	'	'
Equity portion of bond repurchase	0.5	0.5	'	0.5	'	'	'	'
Other comprehensive income, net of tax	12.7	12.7	'	'	'	'	12.7	'
Balance at May. 31, 2013	919.5	918.6	44.7	431.6	584.9	-100.1	-42.5	0.9
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	73.2	72.9	'	'	72.9	'	'	0.3
Cash dividends	-11.8	-11.8	'	'	-11.8	'	'	'
Stock option activity	7.8	7.8	'	2.8	'	5	'	'
Restricted stock activity	-0.2	-0.2	'	2	'	-2.2	'	'
Repurchase of shares	-1	-1	'	'	'	-1	'	'
Other comprehensive income, net of tax	13.2	13.2	'	'	'	'	13.2	'
Balance at May. 31, 2014	$1,000.70	$999.50	$44.70	$436.40	$646	($98.30)	($29.30)	$1.20

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Cash flows provided from operating activities:	'	'	'
Net income attributable to AAR and noncontrolling interest	$73.20	$55.50	$68
Adjustments to reconcile net income attributable to AAR and noncontrolling interest to net cash provided from operating activities:	'	'	'
Depreciation and amortization	80.4	79.7	72
Amortization of stock-based compensation	8.7	11.1	12.5
Amortization of debt discount	5.3	9.6	13.2
Amortization of overhaul costs	33	28.9	8.3
Deferred tax provision	9.6	29.5	32.8
Restructuring and impairment charges	'	'	3.7
Loss on extinguishment of debt	'	0.3	0.7
Earnings from joint ventures	-3.1	-6.8	-1.5
Changes in certain assets and liabilities, net of acquisitions:	'	'	'
Accounts receivable	16.7	6	36.3
Inventories	-47.9	16.1	-47.6
Rotable spares and equipment on or available for short-term lease	11.3	10.4	5.6
Equipment on or available for long-term lease	-41.7	0.8	16.5
Accounts and trade notes payable	20.1	-50.7	18.3
Accrued and other liabilities	4.3	11.8	-20.9
Other, primarily program and overhaul costs	-30.1	-39.3	-123.7
Net cash provided from operating activities	139.8	162.9	94.2
Cash flows used in investing activities:	'	'	'
Property, plant and equipment expenditures	-26.5	-37.6	-91.2
Proceeds from disposal of assets	2	11.8	4.1
Payments for acquisitions	-15.3	-21.3	-298.1
Proceeds from aircraft joint ventures	-0.2	15.4	1.6
Other	-0.9	-1.1	-6.6
Net cash used in investing activities	-40.9	-32.8	-390.2
Cash flows (used in) provided from financing activities:	'	'	'
Short-term borrowings (repayments), net	10	-160	180
Proceeds from borrowings	'	181.8	236.8
Reduction in borrowing	-88.9	-114.3	-83.5
Reduction in equity due to convertible bond repurchase	'	-0.5	-1.2
Cash dividends	-11.8	-12.8	-12.1
Purchase of treasury stock	-1	-14.6	-3.7
Stock option exercises	5.1	1.1	3
Other	0.7	-4.4	-12.5
Net cash (used in) provided from financing activities	-85.9	-123.7	306.8
Effect of exchange rate changes on cash	0.9	1.2	-0.5
Increase in cash and cash equivalents	13.9	7.6	10.3
Cash and cash equivalents, beginning of year	75.3	67.7	57.4
Cash and cash equivalents, end of year	$89.20	$75.30	$67.70

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	31-May-14
Summary of Significant Accounting Policies	'
Summary of Significant Accounting Policies	'
	1. Summary of Significant Accounting Policies
	Description of Business
	AAR CORP. is a diversified provider of products and services to the worldwide commercial aviation and government and defense markets. Products and services include: aviation supply chain and parts support programs; maintenance, repair and overhaul of aircraft and landing gear; design and manufacture of specialized mobility and cargo systems and composite and other high-end precision machined structures; expeditionary airlift services; aircraft modifications and aircraft and engine sales and leasing. We serve commercial, defense and governmental aircraft fleet operators, original equipment manufacturers, and independent service providers around the world, and various other domestic and foreign military customers.
	Principles of Consolidation
	The accompanying Consolidated Financial Statements include the accounts of the Company and its majority-owned subsidiaries after elimination of intercompany accounts and transactions. The equity method of accounting is used for investments in other companies in which we have significant influence; generally this represents common stock ownership of at least 20% and not more than 50% (see Note 9 for a discussion of aircraft joint ventures).
	Revenue Recognition
	Sales and related cost of sales for product sales are recognized upon shipment of the product to the customer. Our standard terms and conditions provide that title passes to the customer when the product is shipped to the customer. Sales of certain defense products are recognized upon customer acceptance, which includes transfer of title. Under the majority of our expeditionary airlift services contracts, we are paid and record as revenue a fixed daily amount per aircraft for each day an aircraft is available to perform airlift services. In addition, we are paid and record as revenue an amount which is based on number of hours flown. Sales from services and the related cost of services are generally recognized when customer-owned material is shipped back to the customer. We have adopted this accounting policy because at the time the customer-owned material is shipped back to the customer, all services related to that material are complete as our service agreements generally do not require us to provide services at customer sites. Furthermore, serviced units are typically shipped to the customer immediately upon completion of the related services. Sales and related cost of sales for certain long-term manufacturing contracts, certain large airframe maintenance contracts, and performance-based logistics programs are recognized by the percentage of completion method, either based on the relationship of costs incurred to date to the estimated total costs or the units of delivery method. Lease revenues are recognized as earned. Income from monthly or quarterly rental payments is recorded in the pertinent period according to the lease agreement. However, for leases that provide variable rents, we recognize lease income on a straight-line basis. In addition to a monthly lease rate, some engine leases require an additional rental amount based on the number of hours the engine is used in a particular month. Lease income associated with these contingent rentals is recorded in the period in which actual usage is reported to us by the lessee, which is normally the month following the actual usage.
	Certain supply chain management programs we provide to our customers contain multiple elements or deliverables, such as program and warehouse management, parts distribution, and maintenance and repair services. We recognize revenue for each element or deliverable that can be identified as a separate unit of accounting at the time of delivery based upon the relative fair value of the products and services.
	Included in accounts receivable as of May 31, 2014 and 2013, are $19.7 million and $28.4 million, respectively, of unbilled accounts receivable related to our KC10 supply agreement. These unbilled accounts receivable relate to costs we have incurred on parts that were requested and accepted by our customer to support the program. These costs have not been billed by us because the customer has not issued the final paperwork necessary to allow for billing.
	In addition to the unbilled accounts receivable, included in Other non-current assets on the consolidated balance sheet as of May 31, 2014 and 2013, are $9.9 million and $9.9 million, respectively, of costs in excess of amounts billed for the flight-hour portion of the same KC10 supply agreement. These amounts represent the difference between the amount of revenue recognized by us driven by costs incurred under the flight hour portion of the program, compared to what was billed. These amounts are after adjustments recorded during fiscal 2013 and 2012, as more fully described below.
	Pursuant to U.S. generally accepted accounting principles, we have to assess the recoverability of the costs in excess of amounts billed by projecting future performance of the flight hour portion of the contract, including an estimate of future flight hours and costs over the life of the program. In fiscal 2012, we reduced the profit margin on the flight-hour portion of the contract from 8% to 2% due to higher than expected costs incurred by us to support the fleet, resulting in a $9.5 million pre-tax charge.
	To support the 2% margin, we established cost savings targets as we entered fiscal 2013 to reduce program spend over the life of the program and we had been successful in achieving these targets. However, beginning in the second half of fiscal 2013 we experienced a decrease in flight hour revenue. This decrease was caused by a 28% decline in flight hours flown primarily due to lower operations tempo. As a result of this unexpected and significant decline in flight hour revenue and a revised forecast indicating lower usage in the future for the fleet, we further lowered the revenue and profitability forecast for the flight hour portion of the contract during the fourth quarter of fiscal 2013 resulting in a $29.8 million pre-tax charge. This revised forecast results in a 0% margin over the remaining life of the flight-hour program.
	No additional adjustments have been recorded in fiscal 2014 based on the flight hours and costs incurred to date as well as future expectations for the program. We recorded 0% margin in fiscal 2014 on the flight-hour portion of the contract, which resulted in revenue of $42.4 million in fiscal 2014. We expect to recover the May 31, 2014 balance of the costs in excess of amounts billed of $9.9 million through projected future billings in excess of forecasted costs over the life of the program.
	Notwithstanding the foregoing, we reserve all our rights under the KC10 supply agreement, at law and in equity, including our rights to recover past and future revenues and expenses associated with the program.
	Allowance for Doubtful Accounts
	We maintain an allowance for doubtful accounts to reflect the expected uncollectibility of accounts receivable based on past collection history and specific risks identified among uncollected accounts. In determining the required allowance, we consider factors such as general and industry-specific economic conditions, customer credit history, and our customers' current and expected future financial performance.
	Goodwill and Other Intangible Assets
	In accordance with Accounting Standards Codification ("ASC") 350, Intangibles—Goodwill and Other, goodwill and other intangible assets deemed to have indefinite lives are not amortized, but are subject to annual impairment tests. We review and evaluate our goodwill and indefinite life intangible assets for potential impairment at a minimum annually, on May 31, or more frequently if circumstances indicate that impairment is possible. We use a two-step process to evaluate goodwill for impairment. In the first step, we compare the fair value of each reporting unit with the carrying value of the reporting unit, including goodwill. If the estimated fair value of the reporting unit is less than the carrying value of the reporting unit, we would be required to complete a second step to determine the amount of goodwill impairment. The second step of the test requires the allocation of the reporting unit's fair value to its assets and liabilities, including any unrecognized intangible assets, in a hypothetical analysis that calculates the implied fair value of goodwill as if the reporting unit was being acquired in a business combination. If the implied fair value of goodwill is less than the carrying value, the difference is recorded as an impairment loss.
	We estimate the fair value of each reporting unit using both an income approach based on discounted cash flows and a market approach based on a multiple of earnings. The assumptions we used to estimate the fair value of our reporting units are based on historical performance, as well as forecasts used in our current business plan and require considerable management judgment. We use a discount rate based on our consolidated weighted average cost of capital which is adjusted for each of our reporting units based on their specific risk and size characteristics. The fair value measurements used for our goodwill impairment testing use significant unobservable inputs, which reflect our own assumptions about the inputs that market participants would use in measuring fair value. The fair value of our reporting units is also impacted by our overall market capitalization and may be impacted by volatility in our stock price and assumed control premium, among other items.
	As of May 31, 2014, we have five reporting units as defined by ASC 350. Step one of the impairment test concluded for all of our reporting units the estimated fair value exceeded its net asset carrying value. Accordingly, there was no indication of impairment and the second step was not performed.
	Goodwill by segment is as follows:
		May 31,
		2014			2013
	Aviation Services	$	107.4		$	105.4
	Technology Products		154.3			150.2
		$	261.7		$	255.6
	Intangible assets with finite useful lives are amortized on a straight-line basis over their estimated useful lives. Intangible assets, other than goodwill, are comprised of the following:
		May 31,
		2014			2013
	Amortizable intangible assets:
	Customer relationships	$	124		$	108
	Developed technology		32.8			31
	Lease agreements		21.5			21.5
	FAA certificates		5			5
			183.3			165.5
	Accumulated amortization		(36.2	)		(25.1	)
			147.1			140.4
	Unamortized intangible assets:
	Trademarks		18.3			17.4
		$	165.4		$	157.8
	Customer relationships are being amortized over 5-20 years, developed technology is being amortized over 7-30 years, the lease agreements are being amortized over 18 years, and the FAA certificates are being amortized over 20 years. Amortization expense recorded during fiscal 2014, 2013 and 2012 was $10.4 million, $13.7 million, and $13.0 million, respectively. The estimated aggregate amount of amortization expense for intangible assets in each of the next five fiscal years is $10.5 million in 2015, $10.3 million in 2016, $10.3 million in 2017, $10.3 million in 2018 and $9.8 million in 2019.
	Foreign Currency
	Our foreign subsidiaries utilize the local currency as their functional currency. All balance sheet accounts of foreign subsidiaries transacting business in currencies other than the U.S. dollar are translated at year-end exchange rates. Revenues and expenses are translated at average exchange rates during the year. Translation adjustments are excluded from the results of operations and are recorded in stockholders' equity as a component of accumulated other comprehensive loss.
	Cash and Cash Equivalents
	Cash and cash equivalents consist of highly liquid instruments which have original maturities of three months or less when purchased.
	Financial Instruments and Concentrations of Market or Credit Risk
	Financial instruments that potentially subject us to concentrations of market or credit risk consist principally of trade receivables. While our trade receivables are diverse and represent a number of entities and geographic regions, the majority are with the U.S. Department of Defense and its contractors and entities in the aviation industry. Accounts receivable due from the U.S. Department of Defense were $50.5 million and $49.3 million at May 31, 2014 and 2013, respectively. Additionally, included in accounts receivable as of May 31, 2014 and 2013, are $48.7 million and $56.0 million, respectively, of accounts receivable from a large defense contractor. We perform regular evaluations of customer payment experience, current financial condition, and risk analysis. We may require collateral in the form of security interests in assets, letters of credit, and/or obligation guarantees from financial institutions for transactions executed on other than normal trade terms.
	The carrying amounts of cash and cash equivalents, accounts receivable, short-term borrowings, and accounts and trade notes payable approximate fair value because of the short-term maturity of these instruments. The carrying value of long-term debt bearing a variable interest rate approximates fair value.
	Fair value estimates are made at a specific point in time based on relevant market information about the financial instrument. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates.
	Inventories
	Inventories are valued at the lower of cost or market (estimated net realizable value). Cost is determined by the specific identification, average cost, or first-in, first-out methods. From time-to-time, we purchase aircraft and engines for disassembly to individual parts and components. Costs are assigned to these individual parts and components utilizing list prices from original equipment manufacturers and recent sales history.
	The following is a summary of inventories:
		May 31,
		2014			2013
	Raw materials and parts	$	114.1		$	83.9
	Work-in-process		57.5			84
	Aircraft and engine parts, components and finished goods		323.7			285.8
		$	495.3		$	453.7
	Equipment under Leases
	Lease revenue is recognized as earned. The cost of the asset under lease is the original purchase price plus overhaul costs. Depreciation for aircraft is computed using the straight-line method over the estimated service life of the equipment. The balance sheet classification of equipment under lease is generally based on lease term, with fixed-term leases less than twelve months generally classified as short-term and all others generally classified as long-term.
	Equipment on short-term lease includes aircraft engines and parts on or available for lease to satisfy customers' immediate short-term requirements. The leases are renewable with fixed terms, which generally vary from one to twelve months. Equipment on long-term lease consists of aircraft and engines on lease with commercial airlines generally for more than twelve months and rotable parts used to support long-term supply chain programs. The rotable parts included in equipment on long-term lease are being depreciated on a straight-line basis over their estimated useful lives.
	The following is a summary of equipment on or available for long-term lease:
		May 31,
	2014			2013
Rotable parts	$	73.1		$	41.7
Aircraft		25.3			23
	$	98.4		$	64.7
In accordance with ASC 360, Property, Plant and Equipment, we are required to test for impairment of long-lived assets whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable from its undiscounted cash flows. When applying ASC 360 to our aircraft and engine portfolio, we utilize certain assumptions to estimate future undiscounted cash flows, including current and future lease rates, lease terms, residual values and market conditions and trends impacting future demand.
Future rent due to us under non-cancelable leases during each of the next five fiscal years is $19.9 million in 2015, $20.4 million in 2016, $19.9 million in 2017, $19.3 million in 2018, and $18.6 million in 2019.
Property, Plant and Equipment
We record property, plant and equipment at cost. Depreciation is computed on the straight-line method over useful lives of 10-40 years for buildings and improvements and 3-10 years for equipment, furniture and fixtures, and capitalized software. Aircraft, major components in service, and associated rotable assets to support our expeditionary airlift services are depreciated over their estimated useful lives, which is generally 7-30 years. Leasehold improvements are amortized over the shorter of the estimated useful life or the term of the applicable lease.
Repair and maintenance expenditures are expensed as incurred. Upon sale or disposal, cost and accumulated depreciation are removed from the accounts, and related gains and losses are included in results of operations.
Income Taxes
We are subject to income taxes in the U.S., state, and several foreign jurisdictions. In the ordinary course of business, there can be transactions and calculations where the ultimate tax determination is uncertain. We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns in accordance with applicable accounting guidance for accounting for income taxes, using currently enacted tax rates in effect for the year in which the differences are expected to reverse. We record a valuation allowance when necessary to reduce deferred tax assets to the amount expected to be realized.
The accounting for uncertainty in income taxes requires a more-likely-than-not threshold for financial statement recognition of tax positions taken or expected to be taken in a tax return. Where necessary, we record a liability for the difference between the benefit recognized for financial statement purposes and the tax position taken or expected to be taken on our tax return. To the extent that our assessment of such tax positions changes, the change in estimate is recorded in the period in which the determination is made.
Supplemental Information on Cash Flows
Supplemental information on cash flows is as follows:
	For the Year Ended
	May 31,
	2014			2013			2012
Interest paid	$	33.8		$	28.3		$	16.6
Income taxes paid		17.3			24.1			11.4
Income tax refunds and interest received		7.5			23.2			7.2
During fiscal 2014, treasury stock decreased $1.8 million reflecting the re-issuance of shares upon exercise of stock options, net of shares withheld to satisfy statutory tax obligations, and restricted stock award grants of $2.8 million, partially offset by the purchase of treasury shares of $1.0 million. During fiscal 2013, treasury stock increased $9.7 million reflecting the purchase of treasury shares of $14.6 million, partially offset by the re-issuance of shares upon exercise of stock options, net of shares withheld to satisfy statutory tax obligations, and restricted stock award grants of $4.9 million. During fiscal 2012, treasury stock decreased $10.0 million reflecting the re-issuance of shares upon exercise of stock options, net of shares withheld to satisfy statutory tax obligations, and restricted stock award grants of $13.7 million, partially offset by the purchase of treasury shares of $3.7 million.
Use of Estimates
We have made estimates and utilized certain assumptions relating to the reporting of assets and liabilities and the disclosures of contingent liabilities to prepare these Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States. Actual results could differ from those estimates.
New Accounting Pronouncements
In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers, which provides guidance for revenue recognition. This ASU affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non-financial assets. This ASU will supersede the revenue recognition requirements in ASC 605, Revenue Recognition, and most industry-specific guidance. This ASU also supersedes certain cost guidance included in Subtopic 605-35, Revenue Recognition-Construction-Type and Production-Type Contracts. This new standard will be effective for us beginning June 1, 2017. We are currently evaluating the impact of the adoption of this new standard on our consolidated financial statements.
Shareholders' Rights Plan
Pursuant to a shareholder rights plan adopted in 2007, each outstanding share of our common stock carries with it a Right to purchase one share at a price of $140 per share. The Rights become exercisable (and separate from the shares) when certain specified events occur, including the acquisition of 15% or more of the common stock by a person or group (an "Acquiring Person") or the commencement of a tender or exchange offer for 15% or more of the common stock.
In the event that an Acquiring Person acquires 15% or more of the common stock, or if we are the surviving corporation in a merger involving an Acquiring Person or if the Acquiring Person engages in certain types of self-dealing transactions, each Right entitles the holder to purchase for $140 per share (or the then-current exercise price), shares of our common stock having a market value of $280 (or two times the exercise price), subject to certain exceptions. Similarly, if we are acquired in a merger or other business combination or 50% or more of our assets or earning power is sold, each Right entitles the holder to purchase at the then-current exercise price that number of shares of common stock of the surviving corporation having a market value of two times the exercise price. The Rights do not entitle the holder thereof to vote or to receive dividends. The Rights will expire on August 6, 2017, and may be redeemed by us for $.01 per Right under certain circumstances.

Financing_Arrangements

Financing Arrangements	12 Months Ended
	31-May-14
Financing Arrangements	'
Financing Arrangements	'
	2. Financing Arrangements
	Debt Outstanding
	A summary of the carrying amount of our debt is as follows:
		May 31,
		2014			2013
	Revolving credit facility expiring April 24, 2018 with interest payable monthly	$	130		$	120
	Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly		29.9			39.2
	Note payable due March 9, 2017 with floating interest rate, payable semi-annually on June 1 and December 1		30			40
	Notes payable due January 15, 2022 with interest at 7.25% payable semi-annually on January 15 and July 15		332.6			333.4
	Convertible notes payable due March 1, 2014 with interest at 1.625% payable semi-annually on March 1 and September 1		—			65.9
	Convertible notes payable due March 1, 2016 with interest at 2.25% payable semi-annually on March 1 and September 1		45.7			43.5
	Other1		65.8			66.6
	Total debt		634			708.6
	Current maturities of debt		(69.7	)		(86.4	)
	Long-term debt	$	564.3		$	622.2
	1
	Included in Other is a mortgage loan (secured by Wood Dale, Illinois facility) due August 1, 2015 of $11.0 million and $11.0 million, 1.75% convertible notes due February 1, 2015 of $29.8 million and $29.4 million, and an industrial revenue bond (secured by property, plant and equipment) due August 1, 2018 of $25.0 million and $25.0 million at May 31, 2014 and 2013, respectively.
	The aggregate principal amount of debt maturing during each of the next five fiscal years is $69.9 million in 2015, $70.8 million in 2016, $10.0 million in 2017, $130.0 million in 2018, and $25.0 million in 2019.
	At May 31, 2014, the carrying value of our 7.25% bonds, 1.75% convertible notes and 2.25% convertible notes was $408.1 million and the estimated fair value was approximately $434.8 million. These debt issuances are classified as Level 2 in the fair value hierarchy. This classification is defined as a fair value determined using market-based inputs other than quoted prices that are observable for the liability, either directly or indirectly.
	At May 31, 2014, the remaining variable rate and fixed rate debt had a fair value that approximates the carrying value of $225.9 million. These debt instruments are classified as Level 3 in the fair value hierarchy which is defined as a fair value determined based upon one or more significant unobservable inputs.
	Credit Facilities
	On April 24, 2013, we amended our agreement with various financial institutions, as lenders, and Bank of America, N.A., as administrative agent for the lenders (as amended, the "Credit Agreement"), reducing the aggregate revolving credit commitment under the Credit Agreement from $580.0 million to $475.0 million, and extending the maturity by approximately two years to April 24, 2018. Borrowings under the Credit Agreement bear interest at the offered Eurodollar Rate (defined as the British Bankers Association LIBOR Rate) plus 125 to 225 basis points based on certain financial measurements if a Eurodollar Rate loan, or at the offered fluctuating Base Rate plus 25 to 125 basis points based on certain financial measurements if a Base Rate loan. Borrowings outstanding under this facility at May 31, 2014 were $130.0 million and there were approximately $14.8 million of outstanding letters of credit, which reduced the availability of this facility to $330.2 million. There are no other terms or covenants limiting the availability of this facility. We also have $5.4 million available under a foreign line of credit.
	Borrowing activity under the Credit Agreement during fiscal 2014, 2013 and 2012 is as follows:
		For the Year Ended May 31,
		2014			2013			2012
	Maximum amount borrowed	$	190		$	395		$	525
	Average daily borrowings		135.8			312.3			288.3
	Average interest rate during the year		1.77	%		2.03	%		1.9	%
	On March 28, 2013, we amended our secured credit facility with The Huntington National Bank (the "Huntington Loan Agreement"). The amendment to the Huntington Loan Agreement reduced our secured facility from $65.0 million to $40.0 million while also reducing the interest rate from 325 basis points to 175 basis points over LIBOR. Borrowings under the Huntington Loan Agreement are secured by aircraft and related engines and components owned by us. The Huntington Loan Agreement expires on April 23, 2015. As of May 31, 2014 and 2013, $29.9 million and $39.2 million, respectively, were outstanding under this agreement.
	The Credit Agreement requires us to comply with certain financial covenants, including a fixed charge coverage ratio and a leverage ratio. The Credit Agreement contains certain affirmative and negative covenants, including those relating to financial reporting and notification, payment of indebtedness, taxes and other obligations, compliance with applicable laws, and limitations on additional liens, indebtedness, acquisitions, investments and disposition of assets. The Credit Agreement also requires our significant domestic subsidiaries, and any subsidiaries that guarantee our other indebtedness, to provide a guarantee of payment under the Credit Agreement.
	The Huntington Loan Agreement requires us to comply with certain financial covenants which are consistent with our Credit Agreement and it is not guaranteed by our subsidiaries. The Huntington Loan Agreement also contains certain affirmative and negative covenants, including those relating to financial reporting and notification, payment of indebtedness, taxes and other obligations, compliance with applicable laws, and limitations on additional liens, indebtedness, acquisitions, investments and disposition of assets.
	At May 31, 2014, we were in compliance with the financial and other covenants in these agreements.
	Debt Issuances
	On April 15, 2013, we completed an add-on offering of $150.0 million aggregate principal amount of our 7.25% Senior Notes due 2022 (the "Notes"). The Notes were sold at a price equal to 107.5% of the principal amount thereof, for a yield to maturity of 6.128%. The net proceeds of the offering of the Notes after expenses were $157.6 million, and were used to repay a portion of the borrowings under our unsecured revolving credit agreement.
	The Notes were issued under the indenture dated January 23, 2012, as supplemented as of November 30, 2012 (the "Indenture"), pursuant to which we issued $175.0 million aggregate principal amount of our 7.25% Senior Notes due 2022 (the "Original Notes" and collectively with the Notes, the "Senior Notes"). The Senior Notes were originally sold in private placements to qualified institutional buyers in accordance with Rule 144A under the Securities Act of 1933, as amended (the "Securities Act") and were subsequently exchanged for substantially identical notes that were registered under the Securities Act. The Senior Notes are fully and unconditionally guaranteed, jointly and severally, on a senior unsecured basis by substantially all of our existing domestic and foreign subsidiaries. The Senior Notes are treated as a single series and will vote as one class under the Indenture.
	On February 14, 2013, we completed an exchange agreement with an institutional holder to exchange $22.7 million aggregate principal amount of our 1.75% Convertible Senior Notes, plus cash in the amount of $7.3 million for a new $30.0 million convertible note (the "New Note"). The New Note was issued in a private placement, is subject to customary resale restrictions, and has no registration rights. The New Note matures on February 1, 2015 unless redeemed earlier by us with 30 days' notice to the holder at a call price reflecting a yield to maturity of 3.75% from inception. We may redeem the New Note at any time with a call price at maturity of 104.038%. Upon conversion, the holder of the New Note shall be entitled to receive only cash and not shares of common stock. The New Note bears interest at a coupon rate of 1.75% per year, payable semi-annually on February 1 and August 1.
	Debt Retirements
	We did not retire any convertible notes during fiscal 2014 except for the remaining 1.625% convertible notes which reached maturity on March 1, 2014. During fiscal 2013 and 2012, we retired a portion of the following convertible notes before their maturity date:
		Principal						Cash Paid					Loss on
		Amount											Repurchase
		2013			2012			2013			2012		2013		2012
	1.625% convertible notes due March 1, 2014	$	6.4		$	9.4		$	6.1		$	8.9	$	0.1	$	0.2
	2.25% convertible notes due March 1, 2016		5.5			9.1			4.9			8.1		0.2		0.3
	1.75% convertible notes due February 1, 2026		11			20.6			11			20.3		—		0.2
		$	22.9		$	39.1		$	22		$	37.3	$	0.3	$	0.7
	The loss on repurchase, after consideration for unamortized discount and debt issuance costs, is recorded in Loss on extinguishment of debt on the Consolidated Statements of Income.
	In addition to the aforementioned debt retirements, during fiscal 2013, pursuant to the terms of the applicable indenture, certain holders of our 1.75% Convertible Senior Notes due 2026 (the "Securities") exercised the right to surrender their Securities for purchase by us (the "Put Option"). The Put Option entitled each holder of the Securities to surrender to us for purchase all or any part of such holder's Securities at a purchase price equal to 100% of the principal amount, plus accrued interest. The aggregate purchase price including principal, accrued and unpaid interest for the Securities surrendered for purchase pursuant to the Put Option was $66.2 million. The purchases were funded primarily by cash on hand and free cash flow during the third quarter of fiscal 2013. There was no gain or loss on the repurchase of these notes.
	Convertible Notes
	As of May 31, 2014 and 2013, the short-term and long-term debt and equity component (recorded in capital surplus, net of income tax benefit) consisted of the following:
		May 31,
		2014			2013
	Long-term debt:
	Principal amount	$	79.8		$	148.3
	Unamortized discount		(4.4	)		(9.5	)
	Net carrying amount	$	75.4		$	138.8
	Equity component, net of tax	$	75.3		$	75.3
	The discount on the liability component of long-term debt is being amortized using the effective interest method based on an effective rate. For fiscal years 2014 and 2013, the effective interest rate for our convertible debt was as follows:
		May 31,
		2014			2013
	1.75% convertible notes due February 1, 2015		5	%		5	%
	2.25% convertible notes due March 1, 2016		7.41	%		7.41	%
	As of May 31, 2014 and 2013, for each of our convertible note issuances, the "if converted" value does not exceed its principal amount.
	The interest expense associated with the convertible notes was as follows:
	For the Year
	Ended May 31,
	2014			2013			2012
Coupon interest	$	3.1		$	3.7		$	4.9
Amortization of deferred financing fees		0.3			0.5			0.7
Amortization of discount		5.1			9.3			13.1
Interest expense related to convertible notes	$	8.5		$	13.5		$	18.7
We are subject to a number of covenants under our financing arrangements, including restrictions that relate to the payment of cash dividends, maintenance of minimum net working capital and tangible net worth levels, fixed charge coverage ratio, sales of assets, additional financing, purchase of our shares and other matters. We are in compliance with all financial and other covenants under our financing arrangements.

Derivative_Instruments_and_Hed

Derivative Instruments and Hedging Activities	12 Months Ended
	31-May-14
Derivative Instruments and Hedging Activities	'
Derivative Instruments and Hedging Activities	'
	3. Derivative Instruments and Hedging Activities
	We are exposed to interest rate risk associated with fluctuations in interest rates on our variable rate debt. We utilize two derivative financial instruments to manage our variable interest rate exposure over a medium- to long-term period. We have a floating-to-fixed interest rate swap and an interest rate cap agreement, each hedging $50.0 million of notional principal interest under our revolving Credit Agreement.
	We do not hold or issue derivative instruments for trading purposes and are not a party to any instruments with leverage or prepayment features. In connection with derivative financial instruments, there exists the risk of the possible inability of counterparties to meet the terms of their contracts. We mitigate this risk by performing financial reviews before the contract is entered into, as well as on-going periodic evaluations. We do not expect any significant losses from counterparty defaults.
	We classify the derivatives as assets or liabilities on the balance sheet. Accounting for the change in fair value of the derivatives is a function of whether the instrument qualifies for, and has been designated as, a hedging relationship, and the type of hedging relationship. As of May 31, 2014, all of our derivative instruments were classified as cash flow hedges. The fair value of the interest rate swap and interest rate cap agreements represents the difference in the present values of cash flows calculated at the contracted interest rates and at current market interest rates at the end of the reporting period. We record the fair value of assets and liabilities in accordance with the hierarchy established by the ASC 820, Fair Value Measurement. The fair value of our interest rate derivatives are classified as Level 2, which refers to fair values estimated using significant other observable inputs including quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. The following tables summarize the classification and fair values of our interest rate derivative instruments reported in the Consolidated Balance Sheet at May 31, 2014 and 2013.
					Derivative
			Derivative		Liabilities
		Balance Sheet Classification	Assets
	Derivatives designated as hedging instruments:		May 31, 2014		May 31, 2014
	Interest rate cap	Long-term assets	$	0.1	$	—
	Interest rate swap	Long-term liabilities		—		(2.8	)
					Derivative
			Derivative		Liabilities
		Balance Sheet Classification	Assets
	Derivatives designated as hedging instruments:		May 31, 2013		May 31, 2013
	Interest rate cap	Long-term assets	$	0.1	$	—
	Interest rate swap	Long-term liabilities		—		(3.6	)
	We include gains and losses on the derivative instruments in other comprehensive income. We recognize the gains and losses on our derivative instruments as an adjustment to interest expense in the period the hedged interest payment affects earnings. The impact of the interest rate swap and interest cap agreement on the Consolidated Statement of Comprehensive Income for the years ended May 31, 2014, 2013 and 2012 was an unrealized gain of $0.7 million, an unrealized gain of $0.6 million and an unrealized loss of $3.9 million, respectively. We expect minimal gain or loss to be reclassified into earnings within the next 12 months.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	31-May-14
Stock-Based Compensation	'
Stock-Based Compensation	'
	4. Stock-Based Compensation
	We provide stock-based awards under the AAR CORP. Stock Benefit Plan ("Stock Benefit Plan") and the AAR CORP. 2013 Stock Plan (the "2013 Stock Plan"), each of which has been approved by our stockholders. Under the Stock Benefit Plan and the 2013 Stock Plan, we are authorized to issue stock options to employees and non-employee directors that allow the grant recipients to purchase shares of common stock at a price not less than the fair market value of the common stock on the date of grant. Generally, stock options awarded expire ten years from the date of grant and are exercisable in three, four or five equal annual increments commencing one year after the date of grant. In addition to stock options, the Stock Benefit Plan and the 2013 Stock Plan also provide for the grant of restricted stock awards and performance-based restricted stock awards. The number of performance-based awards earned, subject to vesting, is based on achievement of certain Company-wide financial goals or stock price targets. The Stock Benefit Plan and the 2013 Stock Plan also provide for the grant of stock appreciation units and restricted stock units; however, to date, no such awards have been granted.
	Restricted stock grants are designed, among other things, to align employee interests with the interests of stockholders and to encourage the recipient to build a career with us. Restricted stock typically vests over periods of one to five years from date of grant. Restricted stock grants may be performance-based with vesting to occur over periods of three to six years. All restricted stock that has been granted and earned according to performance criteria carries full dividend and voting rights, regardless of whether it has vested.
	Substantially all stock options and restricted stock are subject to forfeiture prior to vesting if the employee's employment terminates for any reason other than death, disability or retirement. A total of 11,149,000 shares have been granted under the Stock Benefit Plan since its inception. With the stockholder approval of the 2013 Stock Plan, we will make all future stock awards under the 2013 Stock Plan rather than the Stock Benefit Plan. There are 2,500,000 shares available for grant under the 2013 Stock Plan.
	Stock Options
	During fiscal 2014, 2013 and 2012, we granted stock options representing 1,033,015 shares, 972,180 shares, and 169,281 shares, respectively.
	The weighted average fair value per share of stock options granted during fiscal 2014, 2013 and 2012 was $10.24, $4.85 and $11.42, respectively. The fair value of each stock option grant was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:
		Stock Options Granted
		In Fiscal Year
		2014			2013			2012
	Risk-free interest rate		1.4	%		0.6	%		1.5	%
	Expected volatility of common stock		49.1	%		51.4	%		46.1	%
	Dividend yield		1.2	%		2.3	%		1.1	%
	Expected option term in years		5.2			5.4			5.7
	The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant. The expected volatility is based on historical volatility of our common stock, and the expected option term represents the period of time that the stock options granted are expected to be outstanding based on historical exercise trends. The dividend yield represents our anticipated cash dividends at the grant date over the expected option term.
	A summary of stock option activity for the three years ended May 31, 2014 consisted of the following (shares in thousands):
		2014						2013					2012
		Shares			Weighted			Shares			Weighted		Shares			Weighted
					Average						Average					Average
					Exercise Price						Exercise Price					Exercise Price
	Outstanding at beginning of year		2,300		$	16.22			1,703		$	17.96		1,994		$	18.56
	Granted		1,033		$	25.43			972		$	12.95		169		$	28.45
	Exercised		(473	)	$	16.2			(124	)	$	13.72		(339	)	$	19.95
	Cancelled		(107	)	$	18.48			(251	)	$	15.82		(121	)	$	19.73
	Outstanding at end of year		2,753		$	19.59			2,300		$	16.22		1,703		$	17.96
	Options exercisable at end of year		1,019		$	17.88			1,089		$	17.73		880		$	17.1
	The total fair value of stock options that vested during fiscal 2014, 2013 and 2012 was $2.0 million, $3.6 million and $4.0 million, respectively. The total intrinsic value of stock options exercised during fiscal 2014, 2013 and 2012 was $4.3 million, $0.5 million and $3.3 million, respectively. The aggregate intrinsic value of options outstanding was $15.2 million and $10.9 million as of May 31, 2014 and 2013, respectively. The tax benefit realized from stock options exercised during fiscal 2014, 2013 and 2012 was $1.0 million, zero, and $0.5 million, respectively. Expense charged to operations for stock options during fiscal 2014, 2013 and 2012 was $3.8 million, $3.5 million and $4.2 million, respectively, recorded in selling, general and administrative expenses. As of May 31, 2014, we had $10.4 million of unrecognized compensation expense related to stock options that will be amortized over an average period of 2.5 years.
	The following table provides additional information regarding stock options outstanding as of May 31, 2014 (shares in thousands):
		Options Outstanding									Options Exercisable
	Option	Number			Weighted-Average			Weighted-			Number		Weighted-
	Exercise	Outstanding as			Remaining Contractual			Average Exercise			Exercisable as		Average Exercise
	Price Range	of 5/31/14			Life in Years			Price			of 5/31/14		Price
	$  9.00 - $15.00		800			8		$	12.86			125	$	12.63
	$15.01 - $20.00		748			5.6		$	16.17			730	$	16.16
	$20.01 - $34.50		1,205			8.5		$	26.17			164	$	29.49
			2,753			7.6		$	19.59			1,019	$	17.88
	Restricted Stock
	We provide executives and other key employees an opportunity to be awarded performance-based and time-based restricted stock. The performance-based awards are contingent upon the achievement of certain performance objectives, including net income, return on capital, and leverage ratios, or our stock price achieving a certain level over a period of time. During fiscal 2014, 2013 and 2012, we granted 60,808, 53,280, and 362,500 of performance-based restricted shares, respectively. Time-based restricted shares of 60,808, 65,780, and 299,491 were granted to executives and key employees during fiscal 2014, 2013, and 2012, respectively. We also award time-based restricted stock to our non-employee directors as part of their annual compensation. Time-based restricted shares of 45,000, 48,333, and 45,000 were granted to members of the Board of Directors during fiscal 2014, 2013, and 2012, respectively.
	The fair value of restricted shares is the market value of our common stock on the date of grant. Expense related to all restricted share programs during fiscal 2014, 2013 and 2012 was $4.9 million, $7.6 million and $8.4 million, respectively, and recorded in selling, general and administrative expenses.
	Restricted share activity during the fiscal year ended May 31, 2014 was as follows (shares in thousands):
		Number of			Weighted Average
		Shares			Fair Value
					on Grant Date
	Nonvested at May 31, 2013		1,253		$	22.91
	Granted		167		$	24.15
	Vested		(400	)	$	24.36
	Forfeited		(30	)	$	27.65
	Nonvested at May 31, 2014		990		$	22.49
	As of May 31, 2014, we had $6.5 million of unearned compensation related to restricted shares that will be amortized to expense over a weighted average period of 1.4 years.
	Shareholders' Rights Plan
	Pursuant to a shareholder rights plan adopted in 2007, each outstanding share of our common stock carries with it a Right to purchase one share at a price of $140 per share. The Rights become exercisable (and separate from the shares) when certain specified events occur, including the acquisition of 15% or more of the common stock by a person or group (an "Acquiring Person") or the commencement of a tender or exchange offer for 15% or more of the common stock.
	In the event that an Acquiring Person acquires 15% or more of the common stock, or if we are the surviving corporation in a merger involving an Acquiring Person or if the Acquiring Person engages in certain types of self-dealing transactions, each Right entitles the holder to purchase for $140 per share (or the then-current exercise price), shares of our common stock having a market value of $280 (or two times the exercise price), subject to certain exceptions. Similarly, if we are acquired in a merger or other business combination or 50% or more of our assets or earning power is sold, each Right entitles the holder to purchase at the then-current exercise price that number of shares of common stock of the surviving corporation having a market value of two times the exercise price. The Rights do not entitle the holder thereof to vote or to receive dividends. The Rights will expire on August 6, 2017, and may be redeemed by us for $.01 per Right under certain circumstances.

Income_Taxes

Income Taxes	12 Months Ended
	31-May-14
Income Taxes	'
Income Taxes	'
	5. Income Taxes
	The provision for income taxes on pre-tax income includes the following components:
		For the Year Ended
		May 31,
		2014			2013			2012
	Current:
	Federal	$	(0.5	)	$	(13.1	)	$	(9.8	)
	State		0.2			(1.8	)		(0.5	)
	Foreign		22.8			12.1			3
			22.5			(2.8	)		(7.3	)
	Deferred		9.6			29.5			32.8
		$	32.1		$	26.7		$	25.5
	Income tax receivable at May 31, 2014 and 2013 was $14.8 million and $18.0 million, respectively, and is included in deposits, prepaids and other on the Consolidated Balance Sheet.
	The provision for income taxes on pre-tax income differs from the amount computed by applying the U.S. federal statutory income tax rate of 35% for fiscal 2014, 2013 and 2012 to income before taxes, due to the following:
		For the Year Ended
		May 31,
		2014			2013			2012
	Provision for income taxes at the federal statutory rate	$	36.9		$	28.8		$	32.7
	State income taxes, net of federal benefit and refunds		0.2			(1.0	)		(3.5	)
	Federal adjustments		(2.2	)		—			(3.3	)
	Domestic Production Activities Deduction		(1.6	)		—			—
	Research and development credit		(1.0	)		(1.1	)		(0.8	)
	Noncontrolling interest		(0.1	)		(0.2	)		(0.1	)
	Other		(0.1	)		0.2			0.5
	Provision for income taxes	$	32.1		$	26.7		$	25.5
	Deferred tax liabilities and assets result primarily from the differences in the timing of the recognition of transactions for financial reporting and income tax purposes and consist of the following components:
		May 31,
		2014			2013
	Deferred tax assets-current attributable to:
	Inventory costs	$	14.4		$	14.8
	Employee benefits		7.9			8.3
	Allowance for doubtful accounts		0.8			1.6
	Advanced billings and other		7			(6.7	)
	Total net deferred tax assets-current	$	30.1		$	18
	Deferred tax assets-noncurrent attributable to:
	Postretirement benefits	$	17.6		$	17.7
	Bond hedge		0.8			1.7
	Foreign intangible assets		37.5			41.5
	AMT, NOL and FTC carrybacks		20.6			37.6
	Other		3			1
	Total deferred tax assets-noncurrent	$	79.5		$	99.5
	Total deferred tax assets	$	109.6		$	117.5
	Deferred tax liabilities attributable to:
	Depreciation	$	(166.9	)	$	(163.5	)
	Convertible notes		(2.1	)		(3.9	)
	Capitalized program development costs		(34.1	)		(28.8	)
	Foreign intangible assets		(37.5	)		(41.5	)
	Other		(1.1	)		—
	Total deferred tax liabilities	$	(241.7	)	$	(237.7	)
	Net deferred tax liabilities	$	(132.1	)	$	(120.2	)
	As of May 31, 2014, we have determined that the realization of our deferred tax assets is more likely than not, and that a valuation allowance is not required based upon our history of operating earnings, our expectations for continued future earnings, the nature of certain of our deferred tax assets and the scheduled reversal of deferred tax liabilities, primarily related to depreciation.
	Our fiscal 2014 effective income tax rate was 30.5% which included a $2.7 million reduction in income tax expense related to changes in estimates originally used in the tax provision which were adjusted to actual on the federal income tax return. In addition, our higher forecasted taxable income in fiscal 2014 provided a tax benefit of $1.6 million related to the Domestic Production Activities Deduction in accordance with Internal Revenue Code Section 199. Our fiscal 2013 effective income tax rate was 32.5%, which included a $1.3 million reduction in income tax expense related to the reduction of our state income tax rate from continued implementation of state tax planning strategies. Our fiscal 2012 effective income tax rate was 27.2%, which included a $3.3 million reduction in income tax expense primarily relating to revisions in book versus tax differences, and a $4.0 million reduction in income tax expense, primarily related to the reduction in our state income tax rate from the implementation of state tax planning strategies. Our state tax planning strategies included a new corporate structure and the relocation of one of our significant business units.
	Fiscal years 2013 and subsequent are open for examination. Various states and foreign jurisdictions also remain open subject to their applicable statute of limitations.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	31-May-14
Earnings Per Share	'
Earnings Per Share	'
	6. Earnings Per Share
	The computation of basic earnings per share is based on the weighted average number of common shares outstanding during each period. The computation of diluted earnings per share is based on the weighted average number of common shares outstanding during the period plus, when their effect is dilutive, incremental shares consisting of shares subject to stock options, shares issuable upon vesting of restricted stock awards and shares to be issued upon conversion of convertible debt.
	We use the "if-converted" method in calculating the diluted earnings per share effect of the assumed conversion of our contingently convertible debt issued in fiscal 2006 because the principal for that issuance can be settled in stock, cash or a combination thereof. Under the "if converted" method, the after-tax effect of interest expense related to the convertible securities is added back to net income, and the convertible debt is assumed to have been converted into common shares at the beginning of the period.
	In accordance with ASC 260-10-45, Share-Based Payment Arrangements and Participating Securities and the Two-Class Method, our unvested restricted stock awards are deemed participating securities since these shares are entitled to participate in dividends declared on common shares. During periods of net income, the calculation of earnings per share for common stock excludes income attributable to unvested restricted stock awards from the numerator and excludes the dilutive impact of those shares from the denominator. During periods of net loss, no effect is given to the participating securities because they do not share in the losses of the Company.
	The following tables provide a reconciliation of the computations of basic and diluted earnings per share information for each of the years in the three-year period ended May 31, 2014 (shares in millions).
		For the Year Ended
		May 31,
		2014			2013			2012
	Basic EPS:
	Net income attributable to AAR and noncontrolling interest	$	73.2		$	55.5		$	68
	Less income attributable to participating shares		(1.5	)		(2.0	)		(2.5	)
	Less income attributable to noncontrolling interest		(0.3	)		(0.5	)		(0.3	)
	Net income attributable to AAR available to common shareholders	$	71.4		$	53		$	65.2
	Basic shares:
	Weighted average common shares outstanding		38.6			38.3			38.8
	Earnings per share—basic	$	1.85		$	1.38		$	1.68
	Diluted EPS:
	Net income attributable to AAR and noncontrolling interest	$	73.2		$	55.5		$	68
	Less income attributable to participating shares		(1.5	)		(1.9	)		(2.3	)
	Less income attributable to noncontrolling interest		(0.3	)		(0.5	)		(0.3	)
	Add after-tax interest on convertible debt		—			3.2			5.8
	Net income attributable to AAR available to common shareholders	$	71.4		$	56.3		$	71.2
	Diluted shares:
	Weighted average common shares outstanding		38.6			38.3			38.8
	Additional shares from the assumed exercise of stock options		0.5			0.1			0.2
	Additional shares from the assumed conversion of convertible debt		—			2.2			4.1
	Weighted average common shares outstanding—diluted		39.1			40.6			43.1
	Earnings per share—diluted	$	1.83		$	1.38		$	1.65
	At May 31, 2014, 2013 and 2012, respectively, options to purchase 180,000 shares, 872,200 shares, and 1,627,000 shares of common stock were outstanding, but were not included in the computation of diluted earnings per share, because the exercise price of these options was greater than the average market price of the common shares for the period then ended.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	31-May-14
Employee Benefit Plans	'
Employee Benefit Plans	'
	7. Employee Benefit Plans
	Defined Benefit Plans
	Prior to January 1, 2000, the pension plan for domestic salaried and non-union hourly employees had a benefit formula based primarily on years of service and compensation. Effective January 1, 2000, we converted our defined benefit plan for substantially all domestic salaried and certain hourly employees to a cash balance pension plan. Under the cash balance pension plan, the retirement benefit is expressed as a dollar amount in an account that grows with annual pay-based credits and interest on the account balance. The interest crediting rate under our cash balance plan is determined quarterly and is equal to 100% of the average 30-year treasury rate for the second month preceding the applicable quarter published by the Internal Revenue Service. The average interest crediting rate under our cash balance plan for the fiscal year ended May 31, 2014 was 4.5%. Effective June 1, 2005, the existing cash balance plan was frozen and the annual pay-based credits were discontinued. Also effective June 1, 2005, the defined contribution plan was modified to include increased employer contributions and an enhanced profit sharing formula. Defined pension benefits for certain union hourly employees are based primarily on a fixed amount per year of service.
	Certain foreign operations of domestic subsidiaries also have a defined benefit pension plan. Benefit formulas are based generally on years of service and compensation. It is the policy of these subsidiaries to fund at least the minimum amounts required by local laws and regulations.
	We provide eligible outside directors with benefits upon retirement on or after age 65 provided they have completed at least five years of service as a director. Benefits are paid quarterly in cash equal to 25% of the annual retainer fee payable to active outside directors. Payment of benefits commences upon retirement and continues for a period equal to the total number of years of the retired director's service up to a maximum of ten years, or death, whichever occurs first. In fiscal 2001, we terminated this plan for any new members of the Board of Directors first elected after May 31, 2001. No current directors participate in this plan.
	The change to our projected benefit obligation and the fair value of our plan assets for our pension plan in the United States and other countries was as follows:
		May 31,
		2014			2013
	Change in projected benefit obligation:
	Projected benefit obligation at beginning of year	$	130.2		$	123
	Service cost		2.2			2
	Interest cost		5.1			5
	Participant contributions		0.4			0.4
	Net actuarial loss		5.7			3.4
	Benefit payments		(5.1	)		(5.8	)
	Plan change		0.6			—
	Foreign currency adjustment		2.8			2.2
	Projected benefit obligation at end of year	$	141.9		$	130.2
	Change in the fair value of plan assets:
	Fair value of plan assets at beginning of year	$	101.6		$	87.7
	Actual return on plan assets		10.5			12.9
	Employer contributions		6.2			4.5
	Participant contributions		0.4			0.4
	Benefit payments		(5.1	)		(5.8	)
	Foreign currency adjustment		2.4			1.9
	Fair value of plan assets at end of year	$	116		$	101.6
	Funded status at end of year	$	(25.9	)	$	(28.6	)
	Amounts recognized in the Consolidated Balance Sheets consisted of the following:
		May 31,
		2014			2013
	Accrued liabilities	$	(3.4	)	$	(3.2	)
	Other liabilities and deferred income		(22.5	)		(25.4	)
	Funded status at end of year	$	(25.9	)	$	(28.6	)
	During fiscal 2014, we reclassified $2.1 million from accumulated other comprehensive loss into earnings and recorded additional unrealized losses of $3.6 million in accumulated other comprehensive loss. Amounts recognized in accumulated other comprehensive loss, net of tax of $18.4 million and $18.8 million, at May 31, 2014 and 2013, respectively, consisted of the following:
		May 31,
		2014			2013
	Actuarial loss	$	35		$	33.9
	Prior service cost		1.1			0.7
	Total	$	36.1		$	34.6
	The following tables provide the projected benefit obligation, accumulated benefit obligation, and fair value of plan assets for all pension plans with a projected benefit obligation or accumulated benefit obligation in excess of plan assets.
		May 31,
	Projected benefit obligation in excess of plan assets	2014			2013
	Projected benefit obligation	$	141.9		$	130.2
	Fair value of plan assets		116			101.6
		May 31,
	Accumulated benefit obligation in excess of plan assets	2014			2013
	Projected benefit obligation	$	85.3		$	83.8
	Accumulated benefit obligation		84.8			83.4
	Fair value of plan assets		63.3			57.5
	The accumulated benefit obligation for all pension plans was $134.4 million and $124.7 million as of May 31, 2014 and 2013, respectively.
	Net Periodic Benefit Cost
	Pension expense charged the statement of income includes the following components:
		For the Year
		Ended May 31,
		2014			2013			2012
	Service cost	$	2.2		$	2		$	1.6
	Interest cost		5.1			5			5.5
	Expected return on plan assets		(5.8	)		(6.0	)		(6.6	)
	Amortization of prior service cost		0.1			0.2			0.2
	Recognized net actuarial loss		2			1.9			1
		$	3.6		$	3.1		$	1.7
	The estimated amounts to be amortized from accumulated other comprehensive loss into expense during fiscal 2015 are as follows:
	Net actuarial loss	$	2
Prior service cost		0.2
Total	$	2.2
Assumptions
The assumptions used in accounting for our plans are estimates of factors including, among other things, the amount and timing of future benefit payments. The following table presents the key weighted-average assumptions used in the measurement of our projected benefit obligations:
	May 31,
	2014			2013
Discount rate:
Domestic plans		4.2	%		4.3	%
International plans		3.2			3.7
Rate of compensation increase:
Domestic plans		2.5	%		2.5	%
International plans		3			3
A summary of the weighted-average assumptions used to determine net periodic pension expense is as follows:
	For the Year
	Ended May 31,
	2014			2013			2012
Discount rate:
Domestic plans		4.3	%		4.1	%		5.3	%
International plans		3.7			4.1			5.5
Rate of compensation increase:
Domestic plans		2.5	%		2.5	%		3.5	%
International plans		3			3			3
Expected long-term rate on plan assets:
Domestic plans		7.5	%		8	%		8	%
International plans		3.7			4.2			5.8
The discount rate was determined by projecting the expected future benefit payments as defined for the projected benefit obligation, discounting those expected payments using a theoretical zero-coupon spot yield curve derived from a universe of high-quality bonds as of the measurement date, and solving for the single equivalent discount rate that resulted in the same projected benefit obligation.
Plan Assets
The following table sets forth the actual asset allocation and target allocations for our U.S. pension plans:
	May 31,
							Target Asset
	2014			2013			Allocation
Equity securities		64	%		61	%		45 - 75	%
Fixed income securities		17			20			15 - 25	%
Other		19			19			0 - 25	%
		100	%		100	%
The assets of U.S pension plans are invested in compliance with the Employee Retirement Income Security Act of 1974 (ERISA). The investment goals are to provide a total return that, over the long term, optimizes the long-term return on plan assets at an acceptable risk, and to maintain a broad diversification across asset classes and among investment managers. We believe that there are no significant concentrations of risk within our plan assets as of May 31, 2014. Direct investments in our securities and the use of derivatives for the purpose of speculation are not permitted. The assets of the U.S. pension plans are invested primarily in equity and fixed income mutual funds, individual common stocks, and fund-of-funds hedge funds.
The assets of the non-domestic plan are invested in funds-of-funds where each fund holds a portfolio of equity and fixed income mutual funds.
To develop our expected long-term rate of return assumption on domestic plans, we use long-term historical return information for our targeted asset mix and current market conditions. The expected return for each asset class is weighted based on the target asset allocation to develop the expected long-term rate of return on plan assets assumption. The actual return on plan assets for the years ending May 31, 2014 and 2013 has exceeded our projected long-term rate of return on assets due to strong corporate bond and equity markets that generated asset returns in excess of historical trends and have exceeded the returns we expect these assets to achieve over the long-term.
The following table sets forth by level, within the fair value hierarchy, pension plan assets at their fair value as of May 31, 2014:
	Level 11			Level 22			Level 33			Total
Equity securities:
U.S. common stock	$	6.5		$	—		$	—		$	6.5
U.S. mutual funds		24			—			—			24
International common stock		0.6			—			—			0.6
International mutual funds		9.1			—			—			9.1
Fixed income:
Government securities mutual funds		7.4			—			—			7.4
Corporate bonds mutual funds		3.6			—			—			3.6
Funds-of-funds		—			50.6			7.5			58.1
Hedge funds		—			—			3.6			3.6
Cash and cash equivalents		3.1			—			—			3.1
Total investments	$	54.3		$	50.6		$	11.1		$	116
The following table sets forth by level, within the fair value hierarchy, pension plan assets at their fair value as of May 31, 2013:
	Level 11			Level 22			Level 33			Total
Equity securities:
U.S. common stock	$	6.1		$	—		$	—		$	6.1
U.S. mutual funds		21.7			—			—			21.7
International common stock		0.7			—			—			0.7
International mutual funds		6.7			—			—			6.7
Fixed income:
Government securities mutual funds		7.2			—			—			7.2
Corporate bonds mutual funds		4			—			—			4
Hedge funds		—			—			2.4			2.4
Funds-of-funds		—			44.1			7.7			51.8
Cash and cash equivalents		1			—			—			1
Total investments	$	47.4		$	44.1		$	10.1		$	101.6
1
Quoted prices in active markets for identical assets that we have the ability to access as of the reporting date.
2
Inputs other than quoted prices included within Level 1 that are directly observable for the asset or indirectly observable through corroboration with observable market data.
3
Unobservable inputs, such as internally developed pricing models or third party valuations for the asset due to little or no market activity for the asset.
The following table presents the reconciliation of Level 3 pension assets measured at fair value for the fiscal years ended May 31, 2014 and 2013:
	Hedge Funds			Fund-of-funds			Total
Balance as of May 31, 2012	$	2.3		$	7.1		$	9.4
Return on plan assets related to:
Assets still held at May 31, 2013		0.1			0.6			0.7
Balance as of May 31, 2013		2.4			7.7			10.1
Sales		(2.4	)		(2.3	)		(4.7	)
Purchases		3.6			1.8			5.4
Return on plan assets related to:
Assets sold by May 31, 2014		—			(0.3	)		(0.3	)
Assets still held at May 31, 2014		—			0.6			0.6
Balance as of May 31, 2014	$	3.6		$	7.5		$	11.1
Valuation Techniques Used to Determine Fair Value
Cash equivalents are investments with maturities of three months or less when purchased. The fair values are based on observable market prices and categorized as Level 1.
With respect to individually held equity securities, including investments in U.S. and international securities, the trustees obtain prices from pricing services, whose prices are obtained from direct feeds from market exchanges, which we are able to independently corroborate. Equity securities held individually are primarily traded on exchanges that contain only actively traded securities, due to the volume trading requirements imposed by these exchanges. Equity securities are valued based on quoted prices in active markets and are categorized as Level 1.
Equity and fixed income mutual funds are maintained by investment companies that hold certain investments in accordance with a stated set of fund objectives, which are consistent with our overall investment strategy. The values of some of these funds are publicly quoted. For equity and fixed income mutual funds which are publicly quoted, the funds are valued based on quoted prices in active markets and have been categorized as Level 1. For equity and fixed income mutual funds which are not publicly quoted, the fund administrators value the funds using the net asset value per fund share, derived from quoted prices in active markets of the underlying securities. These funds have been categorized as Level 2. As our funds-of-funds investments are also derived from quoted prices in active markets, we have categorized the funds-of-funds investments as Level 2.
Hedge fund investments include those seeking to maximize absolute returns using a broad range of strategies to enhance returns and provide additional diversification. The fair value of hedge funds is determined using net asset value or its equivalent subject to certain restrictions, such as a lock-up period. As we may be limited in our ability to redeem the investments at the measurement date or within a reasonable period of time, the hedge fund investments are categorized as Level 3.
Future Benefit Payments and Funding
The following table summarizes our estimated future pension payments by fiscal year:
	Fiscal Year
	2015			2016			2017			2018		2019		2020 to
														2024
Estimated future pension payments	$	10.3		$	5.7		$	5.5		$	6.2	$	5.9	$	33.5
Our contribution policy for the domestic plans is to contribute annually, at a minimum, an amount which is deductible for federal income tax purposes and that is sufficient to meet actuarially computed pension benefits. We anticipate contributing approximately $7.9 million during fiscal 2015.
Postretirement Benefits Other Than Pensions
We provide health and life insurance benefits for certain eligible retirees. The postretirement plan is unfunded and in fiscal 1995, we completed termination of postretirement health and life insurance benefits attributable to future services of collective bargaining and other domestic employees. The unfunded projected benefit obligation for this plan was $0.9 million and $1.0 million as of May 31, 2014 and 2013, respectively. We have omitted substantially all of the required disclosures related to this plan because the plan is not material to our consolidated financial position or results of operations.
Defined Contribution Plan
The defined contribution plan is a profit sharing plan which is intended to qualify as a 401(k) plan under the Internal Revenue Code. Under the plan, employees may contribute up to 75% of their pretax compensation, subject to applicable regulatory limits. We may make matching contributions up to 5% of compensation as well as discretionary profit sharing contributions. Our contributions vest on a pro-rata basis during the first three years of employment. We also provide profit sharing benefits for certain executives and key employees to supplement the benefits provided by the defined contribution plan. Expense charged to the statement of income for our matching contributions, including profit sharing contributions, was $12.5 million in fiscal 2014, $14.0 million in fiscal 2013 and $13.2 million in fiscal 2012 for these plans.

Acquisitions

Acquisitions	12 Months Ended
	31-May-14
Acquisitions	'
Acquisitions	'
	8. Acquisitions
	On December 16, 2013, we acquired the cargo systems business of Germany-based PFW Aerospace GmbH. The acquired assets included the cargo systems business for the Airbus A320 family of aircraft and aftermarket spares for additional legacy cargo systems produced for other Airbus platforms. The purchase price was $15.3 million and was paid in cash at closing. The unit operates as part of our Technology Products segment. The results of the completed purchase price allocation are as follows:
	Inventories	$	4.2
	Identified intangibles		10.8
	Goodwill		0.3
	On December 2, 2011, we acquired Telair International GmbH ("Telair") and Nordisk Aviation Products, AS ("Nordisk"). Telair is a leader in the design, manufacture and support of cargo loading systems for wide-body and narrow-body aircraft with established positions on the world's most popular current and next-generation passenger and freighter aircraft. Telair operates from facilities in Germany, Sweden and Singapore. Nordisk designs and manufactures heavy duty pallets and lightweight cargo containers for commercial airlines from facilities in Norway and China. The purchase price of the acquisition was $280.0 million paid at closing, plus or minus a working capital adjustment. During the fourth quarter of fiscal 2012, the working capital adjustment was finalized, which increased the purchase price to $296.5 million. The $16.5 million working capital adjustment was paid in the first quarter of fiscal 2013. The unit operates as part of our Technology Products segment.
	During the second quarter of fiscal 2013, we completed the final purchase price allocation for Telair and Nordisk. We made an adjustment between goodwill and identified intangibles of $11.0 million as part of the final purchase price allocation. The results of the final purchase price allocation are as follows:
	Cash	$	1.5
	Accounts receivable		47.1
	Inventories		54.5
	Prepaid expenses		4.1
	Property, plant and equipment		17
	Deferred tax assets		34.3
	Goodwill		103.9
	Identified intangibles		120
	Notes payable		(1.6	)
	Accounts payable		(14.7	)
	Deferred tax liabilities		(34.3	)
	Accrued liabilities		(27.5	)
	Other long-term liabilities		(7.8	)
	On October 11, 2011, we acquired Airinmar Holdings Limited ("Airinmar"), a sophisticated repair, outsourcing and warranty claim manager. Airinmar operates as part of our Aviation Services segment. Total consideration was estimated to be $43.5 million, which included $23.2 million cash paid at closing, and a potential earn-out payment of $20.3 million. The potential earn-out payment was to be based upon Airinmar achieving certain EBITDA (earnings before interest, taxes, depreciation and amortization) levels over a two-year period, as well as retaining certain key customers. A liability of $20.3 million was recognized as an estimate of the acquisition date fair value of the earn-out and was included in Other liabilities and deferred income on our Consolidated Balance Sheet. During the fourth quarter of 2012, this estimate was reduced by $3.4 million and this change in the fair value of the earn-out was recognized in earnings. During the third quarter of fiscal 2013, we agreed with the sellers of Airinmar to a $4.6 million final settlement for the earn-out. The $9.0 million change in the fair value of the earn-out liability was recognized in earnings.
	During the first quarter of fiscal 2013, we completed the final purchase price allocation for Airinmar and the results are as follows:
	Cash	$	3.7
	Accounts receivable		8
	Prepaid expenses		0.9
	Property, plant and equipment		0.6
	Deferred tax assets		5.3
	Goodwill		21.6
	Identified intangibles		20.8
	Accounts payable		(6.7	)
	Deferred tax liabilities		(5.3	)
	Accrued liabilities		(5.4	)

Aircraft_Portfolio

Aircraft Portfolio	12 Months Ended
	31-May-14
Aircraft Portfolio	'
Aircraft Portfolio	'
	9. Aircraft Portfolio
	Within our Aviation Services segment, we own commercial aircraft with joint venture partners as well as aircraft that are wholly-owned. These aircraft are available for lease or sale to commercial air carriers.
	Aircraft Owned through Joint Ventures
	We had ownership interests in four aircraft with joint venture partners at both May 31, 2014 and 2013. Our equity investment in the aircraft owned with joint venture partners was approximately $28.7 million and $27.5 million as of May 31, 2014 and 2013, respectively, and is included in Investment in joint ventures on the Consolidated Balance Sheet. Included in the May 31, 2014 and 2013 amounts are notes receivable in the amount of $12.2 million and $15.3 million, respectively, for aircraft which the joint ventures have sold. Our aircraft joint ventures represent investments in limited liability companies that are accounted for under the equity method of accounting. Our membership interest in each of these joint ventures is 50%, and the primary business of these joint ventures is the acquisition, ownership, lease and disposition of certain commercial aircraft. Aircraft were purchased with cash contributions by the members of the joint ventures and debt financing provided on a limited recourse basis. Under the terms of servicing agreements with certain of the joint ventures, we provide administrative services and technical advisory services, including aircraft evaluations, oversight and logistical support of the maintenance process and records management. We also provide remarketing services with respect to the divestiture of aircraft by the joint ventures. During fiscal 2014, 2013 and 2012, we were paid $0.1 million, $0.5 million and $0.6 million, respectively, for such services. The income tax benefit or expense related to the operations of the joint ventures is recorded by the member companies.
	Distributions from joint ventures are classified as operating or investing activities in the Consolidated Statements of Cash Flows based upon an evaluation of the specific facts and circumstances of each distribution.
	Summarized financial information for these joint ventures is as follows:
		For the Year Ended
		May 31,
		2014			2013		2012
	Sales	$	10.4		$	115.2	$	45.7
	Income before provision for income taxes		6.7			13.5		3.7
	During the third quarter of fiscal 2013, the joint ventures partners sold ten aircraft for $64.0 million, and during the second quarter of fiscal 2013 the joint venture partners sold two aircraft for $13.9 million.
		May 31,
		2014			2013
	Balance sheet information:
	Assets	$	71.3		$	91.3
	Debt		11.4			26.8
	Members' capital		57.5			61.4
	Wholly-Owned Aircraft
	In addition to the aircraft owned with joint venture partners, we own two aircraft at May 31, 2014 and 2013 for our own account that are considered wholly-owned. Our gross carrying value in the aircraft was $25.3 million and $23.0 million at May 31, 2014 and 2013, respectively.
	Information relating to aircraft type, year of manufacture, lessee, lease expiration date and expected disposition upon lease expiration for the four aircraft owned with joint venture partners and two wholly-owned aircraft as of May 31, 2014 is as follows:
	Aircraft Owned with Joint Venture Partners
	Quantity	Aircraft Type		Year		Lessee	Lease Expiration		Post-Lease
				Manufactured			Date (FY)		Disposition
	2	767-300		1991		United Airlines	2016 and 2017		Re-lease
	1	737-400		1993		City Airways	2018		Re-lease
	1	737-400		1997		—	—		Sale/Re-lease
	4
	Wholly-Owned Aircraft
	Quantity	Aircraft Type		Year		Lessee	Lease Expiration		Post-Lease
				Manufactured			Date(FY)		Disposition
	1	737-300		1997		Small Planet Airlines	2015		Re-lease
	1	A320		1997		Smartlynx	2019		Re-lease
	2

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	31-May-14
Commitments and Contingencies	'
Commitments and Contingencies	'
	10. Commitments and Contingencies
	On October 3, 2003, we entered into a sale-leaseback transaction whereby we sold and leased back a facility located in Garden City, New York. The lease is classified as an operating lease. Net proceeds from the sale of the facility were $14.0 million and the cost and related accumulated depreciation of the facility of $9.5 million and $4.6 million, respectively, were removed from the Consolidated Balance Sheet at the time of sale. The gain realized on the sale of $9.1 million has been deferred and is being amortized over the 20-year lease term. As of May 31, 2014 and 2013, the unamortized balance of the deferred gain was approximately $4.3 million and $4.8 million, respectively, and is included in Other liabilities and deferred income on the Consolidated Balance Sheet.
	In addition to the Garden City lease, we lease other facilities and equipment under agreements that are classified as operating leases that expire at various dates through 2034. Future minimum payments under all operating leases at May 31, 2014 are as follows:
	Year	Facilities and
		Equipment
	2015	$	27.1
	2016		19.3
	2017		13.3
	2018		10.9
	2019		9.3
	2020 and thereafter		29.3
	Rental expense for facilities and equipment during fiscal years 2014, 2013 and 2012 was $36.4 million, $35.2 million and $30.3 million, respectively.
	We enter into purchase obligations which arise in the ordinary course of business and represent a binding commitment to acquire inventory, including raw materials, parts and components, as well as equipment to support the operations of our business. The aggregate amount of purchase obligations due in each of the next five fiscal years is $236.4 million in 2015, $21.6 million in 2016, $0.6 million in 2017 and $0 in 2018 and 2019.
	We routinely issue letters of credit and performance bonds in the ordinary course of our business. These instruments are typically issued in conjunction with insurance contracts or other business requirements. The total of these instruments outstanding at May 31, 2014 was approximately $14.8 million.
	We are involved in various claims and legal actions, including environmental matters, arising in the ordinary course of business. In the opinion of management, the ultimate disposition of these matters will not have a material adverse effect on our consolidated financial condition or results of operations.

Other_Noncurrent_Assets

Other Noncurrent Assets	12 Months Ended
	31-May-14
Other Noncurrent Assets	'
Other Noncurrent Assets	'
	11. Other Noncurrent Assets
	At May 31, 2014 and 2013, other noncurrent assets consisted of the following:
		May 31,
		2014		2013
	Assets under deferred compensation plan	$	23.7	$	20.7
	Cash surrender value of life insurance		17.3		16.5
	License fees		13		14.7
	Costs in excess of billings		15.1		9.9
	Debt issuance costs		9.6		11.9
	Notes receivable		5.2		16.8
	Other		16.2		16.2
		$	100.1	$	106.7
	License Fees
	In June 2011, we entered into a ten-year agreement with Unison Industries to be the exclusive worldwide aftermarket distributor for Unison's electrical components, sensors, switches and other systems for aircraft and industrial uses. In connection with the agreement, we agreed to pay Unison Industries $20.0 million for the exclusive distribution rights with $7.0 million paid in June 2011, and $1.3 million payable by January 31 of each calendar year beginning in January 2012 through 2021.
	As of May 31, 2014 and 2013, the unamortized balance of the license is $11.9 million and $13.5 million, respectively, and is being amortized over a ten-year period. The current portion of the deferred payments of $1.3 million is recorded in Accrued liabilities and the long-term portion of $5.9 million is included in Other liabilities and deferred income on the Consolidated Balance Sheet.

Program_Development_Costs

Program Development Costs	12 Months Ended
	31-May-14
Program Development Costs	'
Program Development Costs	'
	12. Program Development Costs
	Our Cargo Systems unit was selected in June 2005 to provide cargo loading systems for the Airbus A400M Military Transport Aircraft ("A400M"). During fiscal 2013, we delivered initial production units to Airbus and began delivering revenue-producing units in fiscal 2014. We expect our portion of the revenue from this program to be approximately $300 million through fiscal 2021. This estimate excludes future revenue from the sales of spares and is based on current sales projections of the A400M and the agreed-upon fixed pricing for the items that we are now responsible for under the amended contract.
	As of May 31, 2014 and 2013, we have capitalized, net of reimbursements, $139.8 million and $130.9 million, respectively, of costs associated with the engineering and development of the cargo system. Capitalized costs are classified between current and non-current assets on the Consolidated Balance Sheets. Current assets include $27.6 million and $6.0 million in Deposits, prepaids and other at May 31, 2014 and 2013, respectively, and non-current assets include $112.2 million and $124.9 million in Capitalized program development costs at May 31, 2014 and 2013, respectively. Sales and related cost of sales will be recognized on the units of delivery method. In determining the recoverability of the capitalized program development costs, we have made certain judgments and estimates concerning expected revenues and the cost to manufacture the A400M cargo system. Differences between actual results and our assumptions may result in our not fully recovering our program development costs, which could adversely affect our operating results and financial condition.

Business_Segment_Information

Business Segment Information	12 Months Ended
	31-May-14
Business Segment Information	'
Business Segment Information	'
	13. Business Segment Information
	Segment Reporting
	Consistent with how our chief operating decision making officer (Chief Executive Officer) evaluates performance and the way we are organized internally, we report our activities in two business segments: Aviation Services and Technology Products.
	Sales in the Aviation Services segment are derived from the sale and lease of a wide variety of new, overhauled and repaired engine and airframe parts and components to the commercial aviation and government and defense markets. We provide customized inventory supply chain management, performance based logistics programs, aircraft component repair management services, and aircraft modifications. The segment also includes repair, maintenance and overhaul of aircraft and landing gear and expeditionary airlift services. Cost of sales consists principally of the cost of product, direct labor, overhead, and aircraft maintenance costs.
	Sales in the Technology Products segment are derived from the engineering, designing and manufacturing of containers, pallets and shelters used to support the U.S. military's requirements for a mobile and agile force and system integration services for specialized command and control systems. The segment also manufactures heavy-duty pallets and lightweight cargo containers for the commercial market, in-plane cargo loading and handling systems for commercial and military applications, and steel and composite machined and fabricated parts, components and sub-systems for various aerospace and defense programs. Cost of sales consists principally of the cost of material to manufacture products, direct labor and overhead.
	The accounting policies for the segments are the same as those described in Note 1. Our Chief Executive Officer evaluates performance based on the reportable segments and utilizes gross profit as a primary profitability measure. The assets and certain expenses related to corporate activities are not allocated to the segments. Our reportable segments are aligned principally around differences in products and services.
	Gross profit is calculated by subtracting cost of sales from sales. Selected financial information for each segment is as follows:
		For the Year Ended May 31,
		2014			2013			2012
	Net sales:
	Aviation Services	$	1,560.00		$	1,614.40		$	1,536.00
	Technology Products		475			522.9			529
		$	2,035.00		$	2,137.30		$	2,065.00
		For the Year Ended May 31,
		2014			2013			2012
	Gross profit:
	Aviation Services	$	258.9		$	227.5		$	237.3
	Technology Products		81.3			86.7			81.3
		$	340.2		$	314.2		$	318.6
		May 31,
		2014			2013			2012
	Total assets:
	Aviation Services	$	1,266.90		$	1,262.80		$	1,360.10
	Technology Products		751.5			716.6			675.4
	Corporate		181.1			157.5			160.2
		$	2,199.50		$	2,136.90		$	2,195.70
		For the Year Ended May 31,
		2014			2013			2012
	Capital expenditures:
	Aviation Services	$	17.8		$	28.8		$	77.5
	Technology Products		6.4			7.7			12.3
	Corporate		2.3			1.1			1.4
		$	26.5		$	37.6		$	91.2
		For the Year Ended May 31,
		2014			2013			2012
	Depreciation and amortization:1
	Aviation Services	$	57.4		$	59.5		$	56
	Technology Products		21.1			19.6			15.7
	Corporate		10.6			11.7			12.8
		$	89.1		$	90.8		$	84.5
	1
	Includes depreciation and amortization of stock-based compensation.
	The following table reconciles segment gross profit to consolidated income before provision for income taxes.
		For the Year Ended May 31,
		2014			2013			2012
	Segment gross profit	$	340.2		$	314.2		$	318.6
	Selling, general and administrative		(197.6	)		(198.4	)		(189.4	)
	Earnings from joint ventures		3.1			6.8			1.5
	Loss on extinguishment of debt		—			(0.3	)		(0.7	)
	Interest expense		(42.0	)		(41.6	)		(37.7	)
	Interest income		1.6			1.5			1.2
	Income before provision for income taxes	$	105.3		$	82.2		$	93.5
	The U.S. Department of Defense, other U.S. government agencies and their contractors are our only customers representing 10% or more of total sales in any of the last three fiscal years. Sales by segment for these customers are as follows:
		For the Year Ended May 31,
		2014			2013			2012
	Aviation Services	$	521.3		$	548.2		$	534.9
	Technology Products		173.6			215			353.6
		$	694.9		$	763.2		$	888.5
	Percentage of total sales		34.1	%		35.7	%		43	%
	Geographic Data
		May 31,
		2014			2013
	Long-lived assets:
United States	$	809		$	834.1
Europe		271.4			267.2
Other		2.2			1.9
	$	1,082.60		$	1,103.20
Sales to unaffiliated customers in foreign countries (including sales through foreign sales offices of domestic subsidiaries), were approximately $668.4 million (32.8% of total sales), $656.5 million (30.7% of total sales) and $435.7 million (21.1% of total sales) in fiscal 2014, 2013 and 2012, respectively.

Selected_Quarterly_Data_Unaudi

Selected Quarterly Data (Unaudited)	12 Months Ended
	31-May-14
Selected Quarterly Data (Unaudited)	'
Selected Quarterly Data (Unaudited)	'
	14. Selected Quarterly Data (Unaudited)
	The unaudited selected quarterly data for fiscal years ended May 31, 2014 and 2013 follows.
	Fiscal 2014
		First		Second		Third		Fourth		Full
		Quarter		Quarter		Quarter		Quarter		Year
	Sales	$	514.5	$	540.7	$	474.4	$	505.4	$	2,035.00
	Gross profit		84.7		91		78.7		85.8		340.2
	Net income attributable to AAR		17.9		20		17.9		17.1		72.9
	Diluted earnings per share		0.45		0.5		0.45		0.43		1.83
	Dividends declared		0.075		0.075		0.075		0.075		0.3
	Market price
	High		25.84		31.3		30.56		31.05		31.3
	Low		20.06		25.51		25.91		24.22		20.06
	Fiscal 2013
		First		Second		Third		Fourth		Full
		Quarter		Quarter		Quarter		Quarter		Year
	Sales	$	550.5	$	512.8	$	520.2	$	553.8	$	2,137.30
	Gross profit		90.3		87.4		76.2		60.3		314.2
	Net income attributable to AAR		18.2		17.8		18.4		0.6		55
	Diluted earnings per share		0.45		0.44		0.46		0.01		1.38	1
	Dividends declared		0.075		0.075		0.075		0.075		0.3
	Market price
	High		14.88		17.17		20.11		20.47		20.47
	Low		10.34		13.55		15.13		16.47		10.34
	1
	The earnings-per-share computation for the year is a separate, annual calculation. Accordingly, the sum of the quarterly earnings-per-share amounts do not necessarily equal the earnings per share for the year.

Allowance_for_Doubtful_Account

Allowance for Doubtful Accounts	12 Months Ended
	31-May-14
Allowance for Doubtful Accounts	'
Allowance for Doubtful Accounts	'
	15. Allowance for Doubtful Accounts
		May 31,
		2014			2013			2012
	Balance, beginning of year	$	8.7		$	6.5		$	5.7
	Provision charged to operations		0.7			6.8			2.4
	Deductions for accounts written off, net of recoveries		(3.2	)		(4.6	)		(1.6	)
	Balance, end of year	$	6.2		$	8.7		$	6.5

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	31-May-14
Summary of Significant Accounting Policies	'
Principles of Consolidation	'
	Principles of Consolidation
	The accompanying Consolidated Financial Statements include the accounts of the Company and its majority-owned subsidiaries after elimination of intercompany accounts and transactions. The equity method of accounting is used for investments in other companies in which we have significant influence; generally this represents common stock ownership of at least 20% and not more than 50% (see Note 9 for a discussion of aircraft joint ventures).
Revenue Recognition	'
	Revenue Recognition
	Sales and related cost of sales for product sales are recognized upon shipment of the product to the customer. Our standard terms and conditions provide that title passes to the customer when the product is shipped to the customer. Sales of certain defense products are recognized upon customer acceptance, which includes transfer of title. Under the majority of our expeditionary airlift services contracts, we are paid and record as revenue a fixed daily amount per aircraft for each day an aircraft is available to perform airlift services. In addition, we are paid and record as revenue an amount which is based on number of hours flown. Sales from services and the related cost of services are generally recognized when customer-owned material is shipped back to the customer. We have adopted this accounting policy because at the time the customer-owned material is shipped back to the customer, all services related to that material are complete as our service agreements generally do not require us to provide services at customer sites. Furthermore, serviced units are typically shipped to the customer immediately upon completion of the related services. Sales and related cost of sales for certain long-term manufacturing contracts, certain large airframe maintenance contracts, and performance-based logistics programs are recognized by the percentage of completion method, either based on the relationship of costs incurred to date to the estimated total costs or the units of delivery method. Lease revenues are recognized as earned. Income from monthly or quarterly rental payments is recorded in the pertinent period according to the lease agreement. However, for leases that provide variable rents, we recognize lease income on a straight-line basis. In addition to a monthly lease rate, some engine leases require an additional rental amount based on the number of hours the engine is used in a particular month. Lease income associated with these contingent rentals is recorded in the period in which actual usage is reported to us by the lessee, which is normally the month following the actual usage.
	Certain supply chain management programs we provide to our customers contain multiple elements or deliverables, such as program and warehouse management, parts distribution, and maintenance and repair services. We recognize revenue for each element or deliverable that can be identified as a separate unit of accounting at the time of delivery based upon the relative fair value of the products and services.
	Included in accounts receivable as of May 31, 2014 and 2013, are $19.7 million and $28.4 million, respectively, of unbilled accounts receivable related to our KC10 supply agreement. These unbilled accounts receivable relate to costs we have incurred on parts that were requested and accepted by our customer to support the program. These costs have not been billed by us because the customer has not issued the final paperwork necessary to allow for billing.
	In addition to the unbilled accounts receivable, included in Other non-current assets on the consolidated balance sheet as of May 31, 2014 and 2013, are $9.9 million and $9.9 million, respectively, of costs in excess of amounts billed for the flight-hour portion of the same KC10 supply agreement. These amounts represent the difference between the amount of revenue recognized by us driven by costs incurred under the flight hour portion of the program, compared to what was billed. These amounts are after adjustments recorded during fiscal 2013 and 2012, as more fully described below.
	Pursuant to U.S. generally accepted accounting principles, we have to assess the recoverability of the costs in excess of amounts billed by projecting future performance of the flight hour portion of the contract, including an estimate of future flight hours and costs over the life of the program. In fiscal 2012, we reduced the profit margin on the flight-hour portion of the contract from 8% to 2% due to higher than expected costs incurred by us to support the fleet, resulting in a $9.5 million pre-tax charge.
	To support the 2% margin, we established cost savings targets as we entered fiscal 2013 to reduce program spend over the life of the program and we had been successful in achieving these targets. However, beginning in the second half of fiscal 2013 we experienced a decrease in flight hour revenue. This decrease was caused by a 28% decline in flight hours flown primarily due to lower operations tempo. As a result of this unexpected and significant decline in flight hour revenue and a revised forecast indicating lower usage in the future for the fleet, we further lowered the revenue and profitability forecast for the flight hour portion of the contract during the fourth quarter of fiscal 2013 resulting in a $29.8 million pre-tax charge. This revised forecast results in a 0% margin over the remaining life of the flight-hour program.
	No additional adjustments have been recorded in fiscal 2014 based on the flight hours and costs incurred to date as well as future expectations for the program. We recorded 0% margin in fiscal 2014 on the flight-hour portion of the contract, which resulted in revenue of $42.4 million in fiscal 2014. We expect to recover the May 31, 2014 balance of the costs in excess of amounts billed of $9.9 million through projected future billings in excess of forecasted costs over the life of the program.
	Notwithstanding the foregoing, we reserve all our rights under the KC10 supply agreement, at law and in equity, including our rights to recover past and future revenues and expenses associated with the program.
Allowance for Doubtful Accounts	'
	Allowance for Doubtful Accounts
	We maintain an allowance for doubtful accounts to reflect the expected uncollectibility of accounts receivable based on past collection history and specific risks identified among uncollected accounts. In determining the required allowance, we consider factors such as general and industry-specific economic conditions, customer credit history, and our customers' current and expected future financial performance.
Goodwill and Other Intangible Assets	'
	Goodwill and Other Intangible Assets
	In accordance with Accounting Standards Codification ("ASC") 350, Intangibles—Goodwill and Other, goodwill and other intangible assets deemed to have indefinite lives are not amortized, but are subject to annual impairment tests. We review and evaluate our goodwill and indefinite life intangible assets for potential impairment at a minimum annually, on May 31, or more frequently if circumstances indicate that impairment is possible. We use a two-step process to evaluate goodwill for impairment. In the first step, we compare the fair value of each reporting unit with the carrying value of the reporting unit, including goodwill. If the estimated fair value of the reporting unit is less than the carrying value of the reporting unit, we would be required to complete a second step to determine the amount of goodwill impairment. The second step of the test requires the allocation of the reporting unit's fair value to its assets and liabilities, including any unrecognized intangible assets, in a hypothetical analysis that calculates the implied fair value of goodwill as if the reporting unit was being acquired in a business combination. If the implied fair value of goodwill is less than the carrying value, the difference is recorded as an impairment loss.
	We estimate the fair value of each reporting unit using both an income approach based on discounted cash flows and a market approach based on a multiple of earnings. The assumptions we used to estimate the fair value of our reporting units are based on historical performance, as well as forecasts used in our current business plan and require considerable management judgment. We use a discount rate based on our consolidated weighted average cost of capital which is adjusted for each of our reporting units based on their specific risk and size characteristics. The fair value measurements used for our goodwill impairment testing use significant unobservable inputs, which reflect our own assumptions about the inputs that market participants would use in measuring fair value. The fair value of our reporting units is also impacted by our overall market capitalization and may be impacted by volatility in our stock price and assumed control premium, among other items.
	As of May 31, 2014, we have five reporting units as defined by ASC 350. Step one of the impairment test concluded for all of our reporting units the estimated fair value exceeded its net asset carrying value. Accordingly, there was no indication of impairment and the second step was not performed.
	Goodwill by segment is as follows:
		May 31,
		2014			2013
	Aviation Services	$	107.4		$	105.4
	Technology Products		154.3			150.2
		$	261.7		$	255.6
	Intangible assets with finite useful lives are amortized on a straight-line basis over their estimated useful lives. Intangible assets, other than goodwill, are comprised of the following:
		May 31,
		2014			2013
	Amortizable intangible assets:
	Customer relationships	$	124		$	108
	Developed technology		32.8			31
	Lease agreements		21.5			21.5
	FAA certificates		5			5
			183.3			165.5
	Accumulated amortization		(36.2	)		(25.1	)
			147.1			140.4
	Unamortized intangible assets:
	Trademarks		18.3			17.4
		$	165.4		$	157.8
	Customer relationships are being amortized over 5-20 years, developed technology is being amortized over 7-30 years, the lease agreements are being amortized over 18 years, and the FAA certificates are being amortized over 20 years. Amortization expense recorded during fiscal 2014, 2013 and 2012 was $10.4 million, $13.7 million, and $13.0 million, respectively. The estimated aggregate amount of amortization expense for intangible assets in each of the next five fiscal years is $10.5 million in 2015, $10.3 million in 2016, $10.3 million in 2017, $10.3 million in 2018 and $9.8 million in 2019.
Foreign Currency	'
	Foreign Currency
	Our foreign subsidiaries utilize the local currency as their functional currency. All balance sheet accounts of foreign subsidiaries transacting business in currencies other than the U.S. dollar are translated at year-end exchange rates. Revenues and expenses are translated at average exchange rates during the year. Translation adjustments are excluded from the results of operations and are recorded in stockholders' equity as a component of accumulated other comprehensive loss.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	Cash and cash equivalents consist of highly liquid instruments which have original maturities of three months or less when purchased.
Financial Instruments and Concentrations of Market or Credit Risk	'
	Financial Instruments and Concentrations of Market or Credit Risk
	Financial instruments that potentially subject us to concentrations of market or credit risk consist principally of trade receivables. While our trade receivables are diverse and represent a number of entities and geographic regions, the majority are with the U.S. Department of Defense and its contractors and entities in the aviation industry. Accounts receivable due from the U.S. Department of Defense were $50.5 million and $49.3 million at May 31, 2014 and 2013, respectively. Additionally, included in accounts receivable as of May 31, 2014 and 2013, are $48.7 million and $56.0 million, respectively, of accounts receivable from a large defense contractor. We perform regular evaluations of customer payment experience, current financial condition, and risk analysis. We may require collateral in the form of security interests in assets, letters of credit, and/or obligation guarantees from financial institutions for transactions executed on other than normal trade terms.
	The carrying amounts of cash and cash equivalents, accounts receivable, short-term borrowings, and accounts and trade notes payable approximate fair value because of the short-term maturity of these instruments. The carrying value of long-term debt bearing a variable interest rate approximates fair value.
	Fair value estimates are made at a specific point in time based on relevant market information about the financial instrument. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates.
Inventories	'
	Inventories
	Inventories are valued at the lower of cost or market (estimated net realizable value). Cost is determined by the specific identification, average cost, or first-in, first-out methods. From time-to-time, we purchase aircraft and engines for disassembly to individual parts and components. Costs are assigned to these individual parts and components utilizing list prices from original equipment manufacturers and recent sales history.
	The following is a summary of inventories:
		May 31,
		2014			2013
	Raw materials and parts	$	114.1		$	83.9
	Work-in-process		57.5			84
	Aircraft and engine parts, components and finished goods		323.7			285.8
		$	495.3		$	453.7
Equipment under Leases	'
	Equipment under Leases
	Lease revenue is recognized as earned. The cost of the asset under lease is the original purchase price plus overhaul costs. Depreciation for aircraft is computed using the straight-line method over the estimated service life of the equipment. The balance sheet classification of equipment under lease is generally based on lease term, with fixed-term leases less than twelve months generally classified as short-term and all others generally classified as long-term.
	Equipment on short-term lease includes aircraft engines and parts on or available for lease to satisfy customers' immediate short-term requirements. The leases are renewable with fixed terms, which generally vary from one to twelve months. Equipment on long-term lease consists of aircraft and engines on lease with commercial airlines generally for more than twelve months and rotable parts used to support long-term supply chain programs. The rotable parts included in equipment on long-term lease are being depreciated on a straight-line basis over their estimated useful lives.
	The following is a summary of equipment on or available for long-term lease:
		May 31,
		2014			2013
	Rotable parts	$	73.1		$	41.7
	Aircraft		25.3			23
		$	98.4		$	64.7
	In accordance with ASC 360, Property, Plant and Equipment, we are required to test for impairment of long-lived assets whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable from its undiscounted cash flows. When applying ASC 360 to our aircraft and engine portfolio, we utilize certain assumptions to estimate future undiscounted cash flows, including current and future lease rates, lease terms, residual values and market conditions and trends impacting future demand.
	Future rent due to us under non-cancelable leases during each of the next five fiscal years is $19.9 million in 2015, $20.4 million in 2016, $19.9 million in 2017, $19.3 million in 2018, and $18.6 million in 2019.
Property, Plant and Equipment	'
	Property, Plant and Equipment
	We record property, plant and equipment at cost. Depreciation is computed on the straight-line method over useful lives of 10-40 years for buildings and improvements and 3-10 years for equipment, furniture and fixtures, and capitalized software. Aircraft, major components in service, and associated rotable assets to support our expeditionary airlift services are depreciated over their estimated useful lives, which is generally 7-30 years. Leasehold improvements are amortized over the shorter of the estimated useful life or the term of the applicable lease.
	Repair and maintenance expenditures are expensed as incurred. Upon sale or disposal, cost and accumulated depreciation are removed from the accounts, and related gains and losses are included in results of operations.
Income Taxes	'
	Income Taxes
	We are subject to income taxes in the U.S., state, and several foreign jurisdictions. In the ordinary course of business, there can be transactions and calculations where the ultimate tax determination is uncertain. We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns in accordance with applicable accounting guidance for accounting for income taxes, using currently enacted tax rates in effect for the year in which the differences are expected to reverse. We record a valuation allowance when necessary to reduce deferred tax assets to the amount expected to be realized.
	The accounting for uncertainty in income taxes requires a more-likely-than-not threshold for financial statement recognition of tax positions taken or expected to be taken in a tax return. Where necessary, we record a liability for the difference between the benefit recognized for financial statement purposes and the tax position taken or expected to be taken on our tax return. To the extent that our assessment of such tax positions changes, the change in estimate is recorded in the period in which the determination is made.
Supplemental Information on Cash Flows	'
	Supplemental Information on Cash Flows
	Supplemental information on cash flows is as follows:
		For the Year Ended
		May 31,
		2014			2013			2012
	Interest paid	$	33.8		$	28.3		$	16.6
	Income taxes paid		17.3			24.1			11.4
	Income tax refunds and interest received		7.5			23.2			7.2
	During fiscal 2014, treasury stock decreased $1.8 million reflecting the re-issuance of shares upon exercise of stock options, net of shares withheld to satisfy statutory tax obligations, and restricted stock award grants of $2.8 million, partially offset by the purchase of treasury shares of $1.0 million. During fiscal 2013, treasury stock increased $9.7 million reflecting the purchase of treasury shares of $14.6 million, partially offset by the re-issuance of shares upon exercise of stock options, net of shares withheld to satisfy statutory tax obligations, and restricted stock award grants of $4.9 million. During fiscal 2012, treasury stock decreased $10.0 million reflecting the re-issuance of shares upon exercise of stock options, net of shares withheld to satisfy statutory tax obligations, and restricted stock award grants of $13.7 million, partially offset by the purchase of treasury shares of $3.7 million.
Use of Estimates	'
	Use of Estimates
	We have made estimates and utilized certain assumptions relating to the reporting of assets and liabilities and the disclosures of contingent liabilities to prepare these Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States. Actual results could differ from those estimates.
New Accounting Pronouncements	'
	New Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update ("ASU") No. 2014-09, Revenue from Contracts with Customers, which provides guidance for revenue recognition. This ASU affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non-financial assets. This ASU will supersede the revenue recognition requirements in ASC 605, Revenue Recognition, and most industry-specific guidance. This ASU also supersedes certain cost guidance included in Subtopic 605-35, Revenue Recognition-Construction-Type and Production-Type Contracts. This new standard will be effective for us beginning June 1, 2017. We are currently evaluating the impact of the adoption of this new standard on our consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	31-May-14
Summary of Significant Accounting Policies	'
Schedule of goodwill by reportable segment	'
		May 31,
		2014			2013
	Aviation Services	$	107.4		$	105.4
	Technology Products		154.3			150.2
		$	261.7		$	255.6
Schedule of intangible assets, other than goodwill	'
		May 31,
		2014			2013
	Amortizable intangible assets:
	Customer relationships	$	124		$	108
	Developed technology		32.8			31
	Lease agreements		21.5			21.5
	FAA certificates		5			5
			183.3			165.5
	Accumulated amortization		(36.2	)		(25.1	)
			147.1			140.4
	Unamortized intangible assets:
	Trademarks		18.3			17.4
		$	165.4		$	157.8
Summary of inventories	'
		May 31,
		2014			2013
	Raw materials and parts	$	114.1		$	83.9
	Work-in-process		57.5			84
	Aircraft and engine parts, components and finished goods		323.7			285.8
		$	495.3		$	453.7
Summary of equipment on or available for long-term lease	'
		May 31,
		2014			2013
	Rotable parts	$	73.1		$	41.7
	Aircraft		25.3			23
		$	98.4		$	64.7
Schedule of supplemental information on cash flow	'
		For the Year Ended
		May 31,
		2014			2013			2012
	Interest paid	$	33.8		$	28.3		$	16.6
	Income taxes paid		17.3			24.1			11.4
	Income tax refunds and interest received		7.5			23.2			7.2

Financing_Arrangements_Tables

Financing Arrangements (Tables)	12 Months Ended
	31-May-14
Financing Arrangements	'
Summary of carrying amount of debt	'
		May 31,
		2014			2013
	Revolving credit facility expiring April 24, 2018 with interest payable monthly	$	130		$	120
	Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly		29.9			39.2
	Note payable due March 9, 2017 with floating interest rate, payable semi-annually on June 1 and December 1		30			40
	Notes payable due January 15, 2022 with interest at 7.25% payable semi-annually on January 15 and July 15		332.6			333.4
	Convertible notes payable due March 1, 2014 with interest at 1.625% payable semi-annually on March 1 and September 1		—			65.9
	Convertible notes payable due March 1, 2016 with interest at 2.25% payable semi-annually on March 1 and September 1		45.7			43.5
	Other1		65.8			66.6
	Total debt		634			708.6
	Current maturities of debt		(69.7	)		(86.4	)
	Long-term debt	$	564.3		$	622.2
	1
	Included in Other is a mortgage loan (secured by Wood Dale, Illinois facility) due August 1, 2015 of $11.0 million and $11.0 million, 1.75% convertible notes due February 1, 2015 of $29.8 million and $29.4 million, and an industrial revenue bond (secured by property, plant and equipment) due August 1, 2018 of $25.0 million and $25.0 million at May 31, 2014 and 2013, respectively.
Schedule of borrowing activity under the Credit Agreement	'
		For the Year Ended May 31,
		2014			2013			2012
	Maximum amount borrowed	$	190		$	395		$	525
	Average daily borrowings		135.8			312.3			288.3
	Average interest rate during the year		1.77	%		2.03	%		1.9	%
Schedule of retirement of debt	'
		Principal						Cash Paid					Loss on
		Amount											Repurchase
		2013			2012			2013			2012		2013		2012
	1.625% convertible notes due March 1, 2014	$	6.4		$	9.4		$	6.1		$	8.9	$	0.1	$	0.2
	2.25% convertible notes due March 1, 2016		5.5			9.1			4.9			8.1		0.2		0.3
	1.75% convertible notes due February 1, 2026		11			20.6			11			20.3		—		0.2
		$	22.9		$	39.1		$	22		$	37.3	$	0.3	$	0.7
Schedule of long-term debt and equity component (recorded in capital surplus, net of income tax benefit) of convertible notes	'
		May 31,
		2014			2013
	Long-term debt:
	Principal amount	$	79.8		$	148.3
	Unamortized discount		(4.4	)		(9.5	)
	Net carrying amount	$	75.4		$	138.8
	Equity component, net of tax	$	75.3		$	75.3
Schedule of discount on the liability component of long-term debt is being amortized using the effective interest method based on an effective rate	'
		May 31,
		2014			2013
	1.75% convertible notes due February 1, 2015		5	%		5	%
	2.25% convertible notes due March 1, 2016		7.41	%		7.41	%
Schedule of interest expense associated with the convertible notes	'
		For the Year
		Ended May 31,
		2014			2013			2012
	Coupon interest	$	3.1		$	3.7		$	4.9
	Amortization of deferred financing fees		0.3			0.5			0.7
	Amortization of discount		5.1			9.3			13.1
	Interest expense related to convertible notes	$	8.5		$	13.5		$	18.7

Derivative_Instruments_and_Hed1

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	31-May-14
Derivative Instruments and Hedging Activities	'
Schedule of fair value carrying amount of our interest rate derivatives	'
					Derivative
			Derivative		Liabilities
		Balance Sheet Classification	Assets
	Derivatives designated as hedging instruments:		May 31, 2014		May 31, 2014
	Interest rate cap	Long-term assets	$	0.1	$	—
	Interest rate swap	Long-term liabilities		—		(2.8	)
					Derivative
			Derivative		Liabilities
		Balance Sheet Classification	Assets
	Derivatives designated as hedging instruments:		May 31, 2013		May 31, 2013
	Interest rate cap	Long-term assets	$	0.1	$	—
	Interest rate swap	Long-term liabilities		—		(3.6	)

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	31-May-14
Stock-Based Compensation	'
Assumptions used in the Black-Scholes option pricing model to estimate the fair value of each stock option grant	'
		Stock Options Granted
		In Fiscal Year
		2014			2013			2012
	Risk-free interest rate		1.4	%		0.6	%		1.5	%
	Expected volatility of common stock		49.1	%		51.4	%		46.1	%
	Dividend yield		1.2	%		2.3	%		1.1	%
	Expected option term in years		5.2			5.4			5.7
Summary of stock option activity	'
	A summary of stock option activity for the three years ended May 31, 2014 consisted of the following (shares in thousands):
		2014						2013					2012
		Shares			Weighted			Shares			Weighted		Shares			Weighted
					Average						Average					Average
					Exercise Price						Exercise Price					Exercise Price
	Outstanding at beginning of year		2,300		$	16.22			1,703		$	17.96		1,994		$	18.56
	Granted		1,033		$	25.43			972		$	12.95		169		$	28.45
	Exercised		(473	)	$	16.2			(124	)	$	13.72		(339	)	$	19.95
	Cancelled		(107	)	$	18.48			(251	)	$	15.82		(121	)	$	19.73
	Outstanding at end of year		2,753		$	19.59			2,300		$	16.22		1,703		$	17.96
	Options exercisable at end of year		1,019		$	17.88			1,089		$	17.73		880		$	17.1
Schedule of additional information regarding stock options outstanding	'
	The following table provides additional information regarding stock options outstanding as of May 31, 2014 (shares in thousands):
		Options Outstanding									Options Exercisable
	Option	Number			Weighted-Average			Weighted-			Number		Weighted-
	Exercise	Outstanding as			Remaining Contractual			Average Exercise			Exercisable as		Average Exercise
	Price Range	of 5/31/14			Life in Years			Price			of 5/31/14		Price
	$  9.00 - $15.00		800			8		$	12.86			125	$	12.63
	$15.01 - $20.00		748			5.6		$	16.17			730	$	16.16
	$20.01 - $34.50		1,205			8.5		$	26.17			164	$	29.49
			2,753			7.6		$	19.59			1,019	$	17.88
Schedule of restricted share activity	'
	Restricted share activity during the fiscal year ended May 31, 2014 was as follows (shares in thousands):
		Number of			Weighted Average
		Shares			Fair Value
					on Grant Date
	Nonvested at May 31, 2013		1,253		$	22.91
	Granted		167		$	24.15
	Vested		(400	)	$	24.36
	Forfeited		(30	)	$	27.65
	Nonvested at May 31, 2014		990		$	22.49

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	31-May-14
Income Taxes	'
Schedule of components of provision for income taxes on pre-tax income	'
		For the Year Ended
		May 31,
		2014			2013			2012
	Current:
	Federal	$	(0.5	)	$	(13.1	)	$	(9.8	)
	State		0.2			(1.8	)		(0.5	)
	Foreign		22.8			12.1			3
			22.5			(2.8	)		(7.3	)
	Deferred		9.6			29.5			32.8
		$	32.1		$	26.7		$	25.5
Schedule of difference between the provision for income taxes on pre-tax income from the amount computed by applying the U.S. federal statutory tax rate	'
		For the Year Ended
		May 31,
		2014			2013			2012
	Provision for income taxes at the federal statutory rate	$	36.9		$	28.8		$	32.7
	State income taxes, net of federal benefit and refunds		0.2			(1.0	)		(3.5	)
	Federal adjustments		(2.2	)		—			(3.3	)
	Domestic Production Activities Deduction		(1.6	)		—			—
	Research and development credit		(1.0	)		(1.1	)		(0.8	)
	Noncontrolling interest		(0.1	)		(0.2	)		(0.1	)
	Other		(0.1	)		0.2			0.5
	Provision for income taxes	$	32.1		$	26.7		$	25.5
Schedule of components of deferred tax liabilities and assets	'
		May 31,
		2014			2013
	Deferred tax assets-current attributable to:
	Inventory costs	$	14.4		$	14.8
	Employee benefits		7.9			8.3
	Allowance for doubtful accounts		0.8			1.6
	Advanced billings and other		7			(6.7	)
	Total net deferred tax assets-current	$	30.1		$	18
	Deferred tax assets-noncurrent attributable to:
	Postretirement benefits	$	17.6		$	17.7
	Bond hedge		0.8			1.7
	Foreign intangible assets		37.5			41.5
	AMT, NOL and FTC carrybacks		20.6			37.6
	Other		3			1
	Total deferred tax assets-noncurrent	$	79.5		$	99.5
	Total deferred tax assets	$	109.6		$	117.5
	Deferred tax liabilities attributable to:
	Depreciation	$	(166.9	)	$	(163.5	)
	Convertible notes		(2.1	)		(3.9	)
	Capitalized program development costs		(34.1	)		(28.8	)
	Foreign intangible assets		(37.5	)		(41.5	)
	Other		(1.1	)		—
	Total deferred tax liabilities	$	(241.7	)	$	(237.7	)
	Net deferred tax liabilities	$	(132.1	)	$	(120.2	)

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	31-May-14
Earnings Per Share	'
Reconciliation of the computations of basic and diluted earnings per share information	'
	The following tables provide a reconciliation of the computations of basic and diluted earnings per share information for each of the years in the three-year period ended May 31, 2014 (shares in millions).
		For the Year Ended
		May 31,
		2014			2013			2012
	Basic EPS:
	Net income attributable to AAR and noncontrolling interest	$	73.2		$	55.5		$	68
	Less income attributable to participating shares		(1.5	)		(2.0	)		(2.5	)
	Less income attributable to noncontrolling interest		(0.3	)		(0.5	)		(0.3	)
	Net income attributable to AAR available to common shareholders	$	71.4		$	53		$	65.2
	Basic shares:
	Weighted average common shares outstanding		38.6			38.3			38.8
	Earnings per share—basic	$	1.85		$	1.38		$	1.68
	Diluted EPS:
	Net income attributable to AAR and noncontrolling interest	$	73.2		$	55.5		$	68
	Less income attributable to participating shares		(1.5	)		(1.9	)		(2.3	)
	Less income attributable to noncontrolling interest		(0.3	)		(0.5	)		(0.3	)
	Add after-tax interest on convertible debt		—			3.2			5.8
	Net income attributable to AAR available to common shareholders	$	71.4		$	56.3		$	71.2
	Diluted shares:
	Weighted average common shares outstanding		38.6			38.3			38.8
	Additional shares from the assumed exercise of stock options		0.5			0.1			0.2
	Additional shares from the assumed conversion of convertible debt		—			2.2			4.1
	Weighted average common shares outstanding—diluted		39.1			40.6			43.1
	Earnings per share—diluted	$	1.83		$	1.38		$	1.65

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	12 Months Ended
	31-May-14
Employee Benefit Plans	'
Schedule of change to the entity's projected benefit obligation and the fair value of plan assets for pension plan in the United States and other countries	'
		May 31,
		2014			2013
	Change in projected benefit obligation:
	Projected benefit obligation at beginning of year	$	130.2		$	123
	Service cost		2.2			2
	Interest cost		5.1			5
	Participant contributions		0.4			0.4
	Net actuarial loss		5.7			3.4
	Benefit payments		(5.1	)		(5.8	)
	Plan change		0.6			—
	Foreign currency adjustment		2.8			2.2
	Projected benefit obligation at end of year	$	141.9		$	130.2
	Change in the fair value of plan assets:
	Fair value of plan assets at beginning of year	$	101.6		$	87.7
	Actual return on plan assets		10.5			12.9
	Employer contributions		6.2			4.5
	Participant contributions		0.4			0.4
	Benefit payments		(5.1	)		(5.8	)
	Foreign currency adjustment		2.4			1.9
	Fair value of plan assets at end of year	$	116		$	101.6
	Funded status at end of year	$	(25.9	)	$	(28.6	)
Schedule of amounts recognized in the Consolidated Balance Sheets	'
		May 31,
		2014			2013
	Accrued liabilities	$	(3.4	)	$	(3.2	)
	Other liabilities and deferred income		(22.5	)		(25.4	)
	Funded status at end of year	$	(25.9	)	$	(28.6	)
Schedule of amounts recognized in accumulated other comprehensive loss	'
		May 31,
		2014			2013
	Actuarial loss	$	35		$	33.9
	Prior service cost		1.1			0.7
	Total	$	36.1		$	34.6
Schedule of projected benefit obligation, accumulated benefit obligation, and fair value of plan assets for all pension plans with a projected benefit obligation or accumulated benefit obligation in excess of plan assets	'
		May 31,
	Projected benefit obligation in excess of plan assets	2014			2013
	Projected benefit obligation	$	141.9		$	130.2
	Fair value of plan assets		116			101.6
		May 31,
	Accumulated benefit obligation in excess of plan assets	2014			2013
	Projected benefit obligation	$	85.3		$	83.8
	Accumulated benefit obligation		84.8			83.4
	Fair value of plan assets		63.3			57.5
Schedule of components of pension expense charged to the statement of income	'
		For the Year
		Ended May 31,
		2014			2013			2012
	Service cost	$	2.2		$	2		$	1.6
	Interest cost		5.1			5			5.5
	Expected return on plan assets		(5.8	)		(6.0	)		(6.6	)
	Amortization of prior service cost		0.1			0.2			0.2
	Recognized net actuarial loss		2			1.9			1
		$	3.6		$	3.1		$	1.7
Schedule of estimated amounts for plans that will be amortized from accumulated other comprehensive loss into expense over the next fiscal year	'
	Net actuarial loss	$	2
	Prior service cost		0.2
	Total	$	2.2
Schedule of key weighted-average assumptions used in the measurement of the entity's projected benefit obligations	'
		May 31,
		2014			2013
	Discount rate:
	Domestic plans		4.2	%		4.3	%
	International plans		3.2			3.7
	Rate of compensation increase:
	Domestic plans		2.5	%		2.5	%
	International plans		3			3
Summary of the weighted average assumptions used to determine net periodic pension expense	'
		For the Year
		Ended May 31,
		2014			2013			2012
	Discount rate:
	Domestic plans		4.3	%		4.1	%		5.3	%
	International plans		3.7			4.1			5.5
	Rate of compensation increase:
	Domestic plans		2.5	%		2.5	%		3.5	%
	International plans		3			3			3
	Expected long-term rate on plan assets:
	Domestic plans		7.5	%		8	%		8	%
	International plans		3.7			4.2			5.8
Schedule of actual asset allocation and target allocations	'
		May 31,
								Target Asset
		2014			2013			Allocation
	Equity securities		64	%		61	%		45 - 75	%
	Fixed income securities		17			20			15 - 25	%
	Other		19			19			0 - 25	%
			100	%		100	%
Schedule of fair value of pension plan assets	'
	The following table sets forth by level, within the fair value hierarchy, pension plan assets at their fair value as of May 31, 2014:
		Level 11			Level 22			Level 33			Total
	Equity securities:
	U.S. common stock	$	6.5		$	—		$	—		$	6.5
	U.S. mutual funds		24			—			—			24
	International common stock		0.6			—			—			0.6
	International mutual funds		9.1			—			—			9.1
	Fixed income:
	Government securities mutual funds		7.4			—			—			7.4
	Corporate bonds mutual funds		3.6			—			—			3.6
	Funds-of-funds		—			50.6			7.5			58.1
	Hedge funds		—			—			3.6			3.6
	Cash and cash equivalents		3.1			—			—			3.1
	Total investments	$	54.3		$	50.6		$	11.1		$	116
	The following table sets forth by level, within the fair value hierarchy, pension plan assets at their fair value as of May 31, 2013:
		Level 11			Level 22			Level 33			Total
	Equity securities:
	U.S. common stock	$	6.1		$	—		$	—		$	6.1
	U.S. mutual funds		21.7			—			—			21.7
	International common stock		0.7			—			—			0.7
	International mutual funds		6.7			—			—			6.7
	Fixed income:
	Government securities mutual funds		7.2			—			—			7.2
	Corporate bonds mutual funds		4			—			—			4
	Hedge funds		—			—			2.4			2.4
	Funds-of-funds		—			44.1			7.7			51.8
	Cash and cash equivalents		1			—			—			1
	Total investments	$	47.4		$	44.1		$	10.1		$	101.6
	1
	Quoted prices in active markets for identical assets that we have the ability to access as of the reporting date.
	2
	Inputs other than quoted prices included within Level 1 that are directly observable for the asset or indirectly observable through corroboration with observable market data.
	3
	Unobservable inputs, such as internally developed pricing models or third party valuations for the asset due to little or no market activity for the asset.
Schedule of reconciliation of Level 3 pension assets measured at fair value	'
		Hedge Funds			Fund-of-funds			Total
	Balance as of May 31, 2012	$	2.3		$	7.1		$	9.4
	Return on plan assets related to:
	Assets still held at May 31, 2013		0.1			0.6			0.7
	Balance as of May 31, 2013		2.4			7.7			10.1
	Sales		(2.4	)		(2.3	)		(4.7	)
	Purchases		3.6			1.8			5.4
	Return on plan assets related to:
	Assets sold by May 31, 2014		—			(0.3	)		(0.3	)
	Assets still held at May 31, 2014		—			0.6			0.6
	Balance as of May 31, 2014	$	3.6		$	7.5		$	11.1
Summary of estimated future pension payments	'
		Fiscal Year
		2015			2016			2017			2018		2019		2020 to
															2024
	Estimated future pension payments	$	10.3		$	5.7		$	5.5		$	6.2	$	5.9	$	33.5

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	31-May-14
PFW Aerospace GmbH	'
Acquisitions	'
Schedule of purchase price allocation	'
	Inventories	$	4.2
	Identified intangibles		10.8
	Goodwill		0.3
Telair and Nordisk	'
Acquisitions	'
Schedule of final purchase price allocation	'
	Cash	$	1.5
	Accounts receivable		47.1
	Inventories		54.5
	Prepaid expenses		4.1
	Property, plant and equipment		17
	Deferred tax assets		34.3
	Goodwill		103.9
	Identified intangibles		120
	Notes payable		(1.6	)
	Accounts payable		(14.7	)
	Deferred tax liabilities		(34.3	)
	Accrued liabilities		(27.5	)
	Other long-term liabilities		(7.8	)
Airinmar	'
Acquisitions	'
Schedule of final purchase price allocation	'
	Cash	$	3.7
	Accounts receivable		8
	Prepaid expenses		0.9
	Property, plant and equipment		0.6
	Deferred tax assets		5.3
	Goodwill		21.6
	Identified intangibles		20.8
	Accounts payable		(6.7	)
	Deferred tax liabilities		(5.3	)
	Accrued liabilities		(5.4	)

Aircraft_Portfolio_Tables

Aircraft Portfolio (Tables)	12 Months Ended
	31-May-14
Aircraft Portfolio	'
Schedule of summarized income statement information of the joint ventures	'
		For the Year Ended
		May 31,
		2014			2013		2012
	Sales	$	10.4		$	115.2	$	45.7
	Income before provision for income taxes		6.7			13.5		3.7
Schedule of summarized balance sheet information of the limited liability companies	'
		May 31,
		2014			2013
	Balance sheet information:
	Assets	$	71.3		$	91.3
	Debt		11.4			26.8
	Members' capital		57.5			61.4
Information relating to aircraft type, year of manufacture, lessee, lease expiration date and expected disposition upon lease expiration	'
	Aircraft Owned with Joint Venture Partners
	Quantity	Aircraft Type		Year		Lessee	Lease Expiration		Post-Lease
				Manufactured			Date (FY)		Disposition
	2	767-300		1991		United Airlines	2016 and 2017		Re-lease
	1	737-400		1993		City Airways	2018		Re-lease
	1	737-400		1997		—	—		Sale/Re-lease
	4
	Wholly-Owned Aircraft
	Quantity	Aircraft Type		Year		Lessee	Lease Expiration		Post-Lease
				Manufactured			Date(FY)		Disposition
	1	737-300		1997		Small Planet Airlines	2015		Re-lease
	1	A320		1997		Smartlynx	2019		Re-lease
	2

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	31-May-14
Commitments and Contingencies	'
Schedule of future minimum payments under operating leases	'
	Year	Facilities and
		Equipment
	2015	$	27.1
	2016		19.3
	2017		13.3
	2018		10.9
	2019		9.3
	2020 and thereafter		29.3

Other_Noncurrent_Assets_Tables

Other Noncurrent Assets (Tables)	12 Months Ended
	31-May-14
Other Noncurrent Assets	'
Schedule of other noncurrent assets	'
		May 31,
		2014		2013
	Assets under deferred compensation plan	$	23.7	$	20.7
	Cash surrender value of life insurance		17.3		16.5
	License fees		13		14.7
	Costs in excess of billings		15.1		9.9
	Debt issuance costs		9.6		11.9
	Notes receivable		5.2		16.8
	Other		16.2		16.2
		$	100.1	$	106.7

Business_Segment_Information_T

Business Segment Information (Tables)	12 Months Ended
	31-May-14
Business Segment Information	'
Selected financial information for each reportable segment	'
		For the Year Ended May 31,
		2014			2013			2012
	Net sales:
	Aviation Services	$	1,560.00		$	1,614.40		$	1,536.00
	Technology Products		475			522.9			529
		$	2,035.00		$	2,137.30		$	2,065.00
		For the Year Ended May 31,
		2014			2013			2012
	Gross profit:
	Aviation Services	$	258.9		$	227.5		$	237.3
	Technology Products		81.3			86.7			81.3
		$	340.2		$	314.2		$	318.6
		May 31,
		2014			2013			2012
	Total assets:
	Aviation Services	$	1,266.90		$	1,262.80		$	1,360.10
	Technology Products		751.5			716.6			675.4
	Corporate		181.1			157.5			160.2
		$	2,199.50		$	2,136.90		$	2,195.70
		For the Year Ended May 31,
		2014			2013			2012
	Capital expenditures:
	Aviation Services	$	17.8		$	28.8		$	77.5
	Technology Products		6.4			7.7			12.3
	Corporate		2.3			1.1			1.4
		$	26.5		$	37.6		$	91.2
		For the Year Ended May 31,
		2014			2013			2012
	Depreciation and amortization:1
	Aviation Services	$	57.4		$	59.5		$	56
	Technology Products		21.1			19.6			15.7
	Corporate		10.6			11.7			12.8
		$	89.1		$	90.8		$	84.5
	1
	Includes depreciation and amortization of stock-based compensation.
Schedule of reconciliation of segment gross profit to consolidated income before provision for income taxes	'
		For the Year Ended May 31,
		2014			2013			2012
	Segment gross profit	$	340.2		$	314.2		$	318.6
	Selling, general and administrative		(197.6	)		(198.4	)		(189.4	)
	Earnings from joint ventures		3.1			6.8			1.5
	Loss on extinguishment of debt		—			(0.3	)		(0.7	)
	Interest expense		(42.0	)		(41.6	)		(37.7	)
	Interest income		1.6			1.5			1.2
	Income before provision for income taxes	$	105.3		$	82.2		$	93.5
Schedule of sales to the U.S. Department of Defense, other U.S. government agencies and their contractors by segment	'
		For the Year Ended May 31,
		2014			2013			2012
	Aviation Services	$	521.3		$	548.2		$	534.9
	Technology Products		173.6			215			353.6
		$	694.9		$	763.2		$	888.5
	Percentage of total sales		34.1	%		35.7	%		43	%
Schedule of geographic data	'
		May 31,
		2014			2013
	Long-lived assets:
	United States	$	809		$	834.1
	Europe		271.4			267.2
	Other		2.2			1.9
		$	1,082.60		$	1,103.20

Selected_Quarterly_Data_Unaudi1

Selected Quarterly Data (Unaudited) (Tables)	12 Months Ended
	31-May-14
Selected Quarterly Data (Unaudited)	'
Schedule of unaudited selected quarterly data	'
	Fiscal 2014
		First		Second		Third		Fourth		Full
		Quarter		Quarter		Quarter		Quarter		Year
	Sales	$	514.5	$	540.7	$	474.4	$	505.4	$	2,035.00
	Gross profit		84.7		91		78.7		85.8		340.2
	Net income attributable to AAR		17.9		20		17.9		17.1		72.9
	Diluted earnings per share		0.45		0.5		0.45		0.43		1.83
	Dividends declared		0.075		0.075		0.075		0.075		0.3
	Market price
	High		25.84		31.3		30.56		31.05		31.3
	Low		20.06		25.51		25.91		24.22		20.06
	Fiscal 2013
		First		Second		Third		Fourth		Full
		Quarter		Quarter		Quarter		Quarter		Year
	Sales	$	550.5	$	512.8	$	520.2	$	553.8	$	2,137.30
	Gross profit		90.3		87.4		76.2		60.3		314.2
	Net income attributable to AAR		18.2		17.8		18.4		0.6		55
	Diluted earnings per share		0.45		0.44		0.46		0.01		1.38	1
	Dividends declared		0.075		0.075		0.075		0.075		0.3
	Market price
	High		14.88		17.17		20.11		20.47		20.47
	Low		10.34		13.55		15.13		16.47		10.34
	1
	The earnings-per-share computation for the year is a separate, annual calculation. Accordingly, the sum of the quarterly earnings-per-share amounts do not necessarily equal the earnings per share for the year.

Allowance_for_Doubtful_Account1

Allowance for Doubtful Accounts (Tables)	12 Months Ended
	31-May-14
Allowance for Doubtful Accounts	'
Schedule of allowance for doubtful accounts	'
		May 31,
		2014			2013			2012
	Balance, beginning of year	$	8.7		$	6.5		$	5.7
	Provision charged to operations		0.7			6.8			2.4
	Deductions for accounts written off, net of recoveries		(3.2	)		(4.6	)		(1.6	)
	Balance, end of year	$	6.2		$	8.7		$	6.5

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	31-May-13	31-May-14	31-May-13	31-May-12
Revenue Recognition	'	'	'	'
Unbilled accounts receivable related to KC10 supply agreement	$28.40	$19.70	$28.40	'
Cost in excess of amount billed	9.9	15.1	9.9	'
Prior margin forecast on flight hour portion of supply contract (as a percent)	'	'	'	8.00%
Margin forecast on flight hour portion of supply contract (as a percent)	'	0.00%	2.00%	2.00%
Margin forecast on remaining life of flight hour portion of supply contract (as a percent)	'	0.00%	'	'
Pre-tax charge	29.8	'	'	9.5
Decrease in flight hours flow due to lower operations tempo (as a percent)	'	'	28.00%	'
Revenue on flight hour portion of contract	'	$42.40	'	'
Minimum	'	'	'	'
Principles of Consolidation	'	'	'	'
Common stock ownership for equity method accounting (as a percent)	'	20.00%	'	'
Maximum	'	'	'	'
Principles of Consolidation	'	'	'	'
Common stock ownership for equity method accounting (as a percent)	'	50.00%	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13
	item
Goodwill by reportable segment	'	'
Goodwill	$261.70	$255.60
Number of reporting units	5	'
Aviation Services	'	'
Goodwill by reportable segment	'	'
Goodwill	107.4	105.4
Technology Products	'	'
Goodwill by reportable segment	'	'
Goodwill	$154.30	$150.20

Summary_of_Significant_Account5

Summary of Significant Accounting Policies (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Amortizable intangible assets:	'	'	'
Gross carrying amount	$183.30	$165.50	'
Accumulated amortization	-36.2	-25.1	'
Net carrying amount	147.1	140.4	'
Unamortized intangible assets:	'	'	'
Trademarks	18.3	17.4	'
Carrying amount of intangible assets, other than goodwill	165.4	157.8	'
Amortization expense	10.4	13.7	13
Estimated aggregate amortization expense for intangible assets in each of the next five fiscal years	'	'	'
2015	10.5	'	'
2016	10.3	'	'
2017	10.3	'	'
2018	10.3	'	'
2019	9.8	'	'
Customer relationships	'	'	'
Amortizable intangible assets:	'	'	'
Gross carrying amount	124	108	'
Customer relationships | Minimum	'	'	'
Unamortized intangible assets:	'	'	'
Useful life	'5 years	'	'
Customer relationships | Maximum	'	'	'
Unamortized intangible assets:	'	'	'
Useful life	'20 years	'	'
Developed technology	'	'	'
Amortizable intangible assets:	'	'	'
Gross carrying amount	32.8	31	'
Developed technology | Minimum	'	'	'
Unamortized intangible assets:	'	'	'
Useful life	'7 years	'	'
Developed technology | Maximum	'	'	'
Unamortized intangible assets:	'	'	'
Useful life	'30 years	'	'
Lease agreements	'	'	'
Amortizable intangible assets:	'	'	'
Gross carrying amount	21.5	21.5	'
Unamortized intangible assets:	'	'	'
Useful life	'18 years	'	'
FAA certificates	'	'	'
Amortizable intangible assets:	'	'	'
Gross carrying amount	$5	$5	'
Unamortized intangible assets:	'	'	'
Useful life	'20 years	'	'

Summary_of_Significant_Account6

Summary of Significant Accounting Policies (Details 4) (USD $)	31-May-14	31-May-13
In Millions, unless otherwise specified
Inventories	'	'
Raw materials and parts	$114.10	$83.90
Work-in-process	57.5	84
Aircraft and engine parts, components and finished goods	323.7	285.8
Total inventories	495.3	453.7
Accounts receivable | Customer | U.S. Department of Defense	'	'
Financial Instruments and Concentrations of Market or Credit Risk	'	'
Accounts receivable due	50.5	49.3
Accounts receivable | Customer | Large defense contractor	'	'
Financial Instruments and Concentrations of Market or Credit Risk	'	'
Accounts receivable due	$48.70	$56

Summary_of_Significant_Account7

Summary of Significant Accounting Policies (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14
Future rent due to us under non-cancelable leases	'
2015	19.9
2016	20.4
2017	19.9
2018	19.3
2019	18.6
Minimum	'
Equipment under leases	'
Period of short-term leases	'1 month
Period of long-term lease	'12 months
Maximum	'
Equipment under leases	'
Period of short-term leases	'12 months

Summary_of_Significant_Account8

Summary of Significant Accounting Policies (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Property, Plant and Equipment	'	'	'
Equipment on or available for long-term lease	$98.40	$64.70	'
Supplemental Information on Cash Flows	'	'	'
Interest paid	33.8	28.3	16.6
Income taxes paid	17.3	24.1	11.4
Income tax refunds and interest received	7.5	23.2	7.2
Building and improvements | Minimum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'10 years	'	'
Building and improvements | Maximum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'40 years	'	'
Equipment | Minimum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'3 years	'	'
Equipment | Maximum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'10 years	'	'
Furniture and fixtures | Minimum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'3 years	'	'
Furniture and fixtures | Maximum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'10 years	'	'
Capitalized software | Minimum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'3 years	'	'
Capitalized software | Maximum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'10 years	'	'
Aircraft and components | Minimum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'7 years	'	'
Aircraft and components | Maximum	'	'	'
Property, Plant and Equipment	'	'	'
Useful life	'30 years	'	'
Rotable parts	'	'	'
Property, Plant and Equipment	'	'	'
Equipment on or available for long-term lease	73.1	41.7	'
Aircraft	'	'	'
Property, Plant and Equipment	'	'	'
Equipment on or available for long-term lease	$25.30	$23	'

Summary_of_Significant_Account9

Summary of Significant Accounting Policies (Details 7) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Repurchase of treasury shares	$1	$14.60	$3.70
Treasury Stock	'	'	'
Total increase (decrease) in treasury stock	-1.8	9.7	-10
Change in treasury stock due to restricted stock awards and exercise of stock options, net of shares withheld to satisfy statutory tax obligations	2.8	4.9	13.7
Repurchase of treasury shares	$1	$14.60	$3.70

Financing_Arrangements_Details

Financing Arrangements (Details) (USD $)

0 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Feb. 14, 2013

31-May-14

31-May-13

31-May-12

31-May-14

31-May-13

Apr. 24, 2013

31-May-14

31-May-14

31-May-14

31-May-14

31-May-14

31-May-14

31-May-14

31-May-13

Mar. 28, 2013

Mar. 28, 2013

31-May-14

31-May-14

31-May-13

Apr. 15, 2013

Jan. 23, 2013

31-May-14

31-May-13

31-May-14

31-May-13

31-May-12

31-May-13

31-May-12

31-May-14

Feb. 14, 2013

31-May-14

31-May-13

31-May-13

31-May-12

31-May-14

31-May-13

31-May-13

31-May-12

Feb. 28, 2013

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-14

31-May-13

31-May-14

31-May-14

31-May-14

31-May-14

31-May-13

31-May-12

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Revolving credit facility expiring April 24, 2018 with interest payable monthly

Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly

Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly

Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly

Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly

Secured credit facility (secured by aircraft and related engines and components) due April 23, 2015 with floating interest rate, payable monthly

Note payable due March 9, 2017 with floating interest rate, payable semi-annually on June 1 and December 1

Note payable due March 9, 2017 with floating interest rate, payable semi-annually on June 1 and December 1

Notes payable due January 15, 2022 with interest at 7.25% payable semi-annually on January 15 and July 15

Notes payable due January 15, 2022 with interest at 7.25% payable semi-annually on January 15 and July 15

Notes payable due January 15, 2022 with interest at 7.25% payable semi-annually on January 15 and July 15

Notes payable due January 15, 2022 with interest at 7.25% payable semi-annually on January 15 and July 15

Convertible notes payable

Convertible notes payable

Convertible notes payable

Convertible notes payable due March 1, 2014 with interest at 1.625% payable semi-annually on March 1 and September 1

Convertible notes payable due March 1, 2014 with interest at 1.625% payable semi-annually on March 1 and September 1

Convertible notes payable due March 1, 2014 with interest at 1.625% payable semi-annually on March 1 and September 1

Convertible notes payable due February 1, 2015 with interest at 1.75% payable semi-annually on February 1 and August 1

Convertible notes payable due February 1, 2015 with interest at 1.75% payable semi-annually on February 1 and August 1

Convertible notes payable due February 1, 2015 with interest at 1.75% payable semi-annually on February 1 and August 1

Convertible notes payable due March 1, 2016 with interest at 2.25% payable semi-annually on March 1 and September 1

Convertible notes payable due March 1, 2016 with interest at 2.25% payable semi-annually on March 1 and September 1

Convertible notes payable due March 1, 2016 with interest at 2.25% payable semi-annually on March 1 and September 1

Convertible notes payable due February 1, 2026 with interest at 1.75% payable semi-annually on February 1 and August 1

Convertible notes payable due February 1, 2026 with interest at 1.75% payable semi-annually on February 1 and August 1

Convertible notes payable due February 1, 2026 with interest at 1.75% payable semi-annually on February 1 and August 1

Convertible notes payable due February 1, 2026 with interest at 1.75% payable semi-annually on February 1 and August 1

Mortgage loan (secured by Wood Dale, Illinois facility) due August 1, 2015 with interest at 5.01%

Mortgage loan (secured by Wood Dale, Illinois facility) due August 1, 2015 with interest at 5.01%

Industrial revenue bond (secured by property, plant and equipment) due August 1, 2018

Industrial revenue bond (secured by property, plant and equipment) due August 1, 2018

Foreign line of credit

Other

Other

7.25% bonds, 1.75% and 2.25% convertible notes

7.25% bonds, 1.75% and 2.25% convertible notes

Remaining variable rate and fixed rate debt

Credit Agreement and its Predecessor

Credit Agreement and its Predecessor

Credit Agreement and its Predecessor

Eurodollar rate

Eurodollar rate

Eurodollar rate

Base rate

Base rate

Base rate

LIBOR

LIBOR

Level 2

Level 3

Minimum

Maximum

Minimum

Maximum

Financing Arrangements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7.25%

7.25%

7.25%

'

'

'

'

'

'

1.63%

'

1.75%

'

'

'

2.25%

1.75%

1.75%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total debt

'

$634

$708.60

'

$130

$120

'

'

'

'

'

'

'

$29.90

$39.20

'

'

'

$30

$40

'

'

$332.60

$333.40

'

'

'

$65.90

'

'

'

'

'

$43.50

'

$45.70

'

'

'

'

'

'

'

'

'

$65.80

$66.60

'

'

'

'

'

'

Current maturities of debt

'

-69.7

-86.4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

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'

'

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'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

564.3

622.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

Aggregate par value of debt maturing in next five fiscal years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2015

'

69.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2016

'

70.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

2017

'

10

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'

'

'

'

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'

'

'

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'

'

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'

'

'

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'

'

'

'

'

'

'

'

'

2018

'

130

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2019

'

25

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Carrying value of long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

79.8

148.3

'

'

'

'

30

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

408.1

'

'

'

'

'

Estimated fair value of long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

434.8

225.9

'

'

'

Maximum borrowing capacity under the credit agreement before amendment

'

'

'

'

'

'

580

'

'

'

'

'

'

'

'

65

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Extended maturity period

'

'

'

'

'2 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum borrowing capacity

'

'

'

'

475

'

'

'

'

'

'

'

'

'

'

40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.4

'

'

'

'

'

'

'

'

Description of variable rate basis

'

'

'

'

'

'

'

'Eurodollar Rate

'

'

'Base Rate

'

'

'

'

'

'LIBOR

'LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basis spread on variable rate (as a percent)

'

'

'

'

'

'

'

'

1.25%

2.25%

'

0.25%

1.25%

'

'

'

1.75%

1.75%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basis spread on variable rate under the credit agreement before amendment (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount outstanding

'

'

'

'

130

'

'

'

'

'

'

'

'

29.9

39.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding letter of credit

'

14.8

'

'

14.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Remaining borrowing capacity

'

'

'

'

330.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Short-term borrowing activity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum amount borrowed

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

190

395

525

Average daily borrowings

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

135.8

312.3

288.3

Average interest rate during the year (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.77%

2.03%

1.90%

Aggregate principal amount of notes sold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

150

175

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument issuance price as a percentage of the principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

107.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective interest rate (as a Percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.13%

'

'

'

'

'

'

'

'

'

3.75%

5.00%

5.00%

7.41%

'

7.41%

1.75%

1.75%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate principal amount of securities exchanged

22.7

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from offering of notes

'

'

181.8

236.8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

157.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash portion received in new debt issuance

7.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notice period for redemption of debt instrument

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Call price at maturity (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

104.04%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Retirement of Principal Amount

'

'

22.9

39.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.4

9.4

'

'

'

'

5.5

9.1

'

'

11

20.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash Paid

'

'

22

37.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.1

8.9

'

'

'

'

4.9

8.1

'

'

11

20.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss on Repurchase

'

'

0.3

0.7

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.1

0.2

'

'

'

'

0.2

0.3

'

0

'

0.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redemption price of debt instrument as a percentage of the principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate purchase price including principal, accrued and unpaid interest pursuant to Put Option

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

66.2

66.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

79.8

148.3

'

'

'

'

30

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

408.1

'

'

'

'

'

Unamortized discount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-4.4

-9.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net carrying amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75.4

138.8

'

'

'

'

'

29.8

29.4

'

'

'

'

'

'

'

11

11

25

25

'

'

'

'

'

'

'

'

'

Equity component, net of tax

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75.3

75.3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest expense

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Coupon interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.1

3.7

4.9

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization of deferred financing fees

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.3

0.5

0.7

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization of discount

'

5.3

9.6

13.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.1

9.3

13.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest expense related to convertible notes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$8.50

$13.50

$18.70

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative_Instruments_and_Hed2

Derivative Instruments and Hedging Activities (Details) (USD $)	31-May-14	31-May-13
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities	'	'
Number of derivative financial instruments	2	'
Interest rate cap | Derivatives designated as hedging instruments:	'	'
Fair value carrying amount of the Company's interest rate derivatives	'	'
Derivative Assets	$0.10	$0.10
Interest rate cap | Derivatives designated as hedging instruments: | Cash flow hedges	'	'
Derivative Instruments and Hedging Activities	'	'
Notional amount under revolving credit agreement	50	'
Interest rate swap | Derivatives designated as hedging instruments:	'	'
Fair value carrying amount of the Company's interest rate derivatives	'	'
Derivative Liabilities	-2.8	-3.6
Interest rate swap | Derivatives designated as hedging instruments: | Cash flow hedges	'	'
Derivative Instruments and Hedging Activities	'	'
Notional amount under revolving credit agreement	$50	'

Derivative_Instruments_and_Hed3

Derivative Instruments and Hedging Activities (Details 2) (Cash flow hedges, USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Cash flow hedges	'	'	'
Impact of the interest rate swap and interest cap agreement on the condensed consolidated statement of income	'	'	'
Amount of unrealized gain recorded in other accumulated comprehensive income (loss)	$0.70	$0.60	($3.90)

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	31-May-14	31-May-13	31-May-12
	item
Share-Based Compensation	'	'	'
Total number of shares granted since inception	11,149,000	'	'
Shares available for grant	2,500,000	'	'
Stock options	'	'	'
Share-Based Compensation	'	'	'
Expiration term	'10 years	'	'
First number of equal annual increments in which stock options are exercisable	3	'	'
First number of equal annual increments in which stock options are exercisable	4	'	'
First number of equal annual increments in which stock options are exercisable	5	'	'
Commencement period after the date of grant for annual increments of stock options becoming exercisable	'1 year	'	'
Weighted average fair value of stock options granted (in dollars per share)	$10.24	$4.85	$11.42
Assumptions used in the Black-Scholes option pricing models to estimate the fair value of each stock option grant	'	'	'
Risk-free interest rate (as a percent)	1.40%	0.60%	1.50%
Expected volatility of common stock (as a percent)	49.10%	51.40%	46.10%
Dividend yield (as a percent)	1.20%	2.30%	1.10%
Expected option term	'5 years 2 months 12 days	'5 years 4 months 24 days	'5 years 8 months 12 days
Shares	'	'	'
Outstanding at beginning of year (in shares)	2,300,000	1,703,000	1,994,000
Granted (in shares)	1,033,015	972,180	169,281
Exercised (in shares)	-473,000	-124,000	-339,000
Cancelled (in shares)	-107,000	-251,000	-121,000
Outstanding at end of year (in shares)	2,753,000	2,300,000	1,703,000
Options exercisable at end of year (in shares)	1,019,000	1,089,000	880,000
Weighted Average Exercise Price	'	'	'
Outstanding at beginning of year (in dollars per share)	$16.22	$17.96	$18.56
Granted (in dollars per share)	$25.43	$12.95	$28.45
Exercised (in dollars per share)	$16.20	$13.72	$19.95
Cancelled (in dollars per share)	$18.48	$15.82	$19.73
Outstanding at end of year (in dollars per share)	$19.59	$16.22	$17.96
Options exercisable at end of year (in dollars per share)	$17.88	$17.73	$17.10
Stock options, additional disclosures	'	'	'
Total fair value of stock options vested	$2	$3.60	$4
Total intrinsic value of stock options exercised	4.3	0.5	3.3
Aggregate intrinsic value of options outstanding	15.2	10.9	'
Tax benefit realized from stock options exercised	1	0	0.5
Compensation expense	3.8	3.5	4.2
Unearned compensation not yet recognized	10.4	'	'
Average remaining amortization period of unearned compensation	'2 years 6 months	'	'
Restricted stock	'	'	'
Stock options, additional disclosures	'	'	'
Compensation expense	4.9	7.6	8.4
Unearned compensation not yet recognized	$6.50	'	'
Average remaining amortization period of unearned compensation	'1 year 4 months 24 days	'	'
Restricted stock | Minimum	'	'	'
Share-Based Compensation	'	'	'
Vesting period	'1 year	'	'
Restricted stock | Maximum	'	'	'
Share-Based Compensation	'	'	'
Vesting period	'5 years	'	'
Performance-based restricted stock | Minimum	'	'	'
Share-Based Compensation	'	'	'
Vesting period	'3 years	'	'
Performance-based restricted stock | Maximum	'	'	'
Share-Based Compensation	'	'	'
Vesting period	'6 years	'	'

StockBased_Compensation_Detail1

Stock-Based Compensation (Details 2) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	31-May-14
Options Outstanding	'
Number Outstanding at the end of the period (in shares)	2,753
Weighted-Average Remaining Contractual Life in Years	'7 years 7 months 6 days
Weighted-Average Exercise Price (in dollars per Share)	$19.59
Options Exercisable	'
Number Outstanding at the end of the period (in shares)	1,019
Weighted-Average Exercise Price (in dollar per Share)	$17.88
$9.00 - $15.00	'
Share-Based Compensation	'
Option Exercise Price Range, low end of range (in dollars per share)	$9
Option Exercise Price Range, high end of range (in dollars per share)	$15
Options Outstanding	'
Number Outstanding at the end of the period (in shares)	800
Weighted-Average Remaining Contractual Life in Years	'8 years
Weighted-Average Exercise Price (in dollars per Share)	$12.86
Options Exercisable	'
Number Outstanding at the end of the period (in shares)	125
Weighted-Average Exercise Price (in dollar per Share)	$12.63
$15.01 - $20.00	'
Share-Based Compensation	'
Option Exercise Price Range, low end of range (in dollars per share)	$15.01
Option Exercise Price Range, high end of range (in dollars per share)	$20
Options Outstanding	'
Number Outstanding at the end of the period (in shares)	748
Weighted-Average Remaining Contractual Life in Years	'5 years 7 months 6 days
Weighted-Average Exercise Price (in dollars per Share)	$16.17
Options Exercisable	'
Number Outstanding at the end of the period (in shares)	730
Weighted-Average Exercise Price (in dollar per Share)	$16.16
$20.01 - $34.50	'
Share-Based Compensation	'
Option Exercise Price Range, low end of range (in dollars per share)	$20.01
Option Exercise Price Range, high end of range (in dollars per share)	$34.50
Options Outstanding	'
Number Outstanding at the end of the period (in shares)	1,205
Weighted-Average Remaining Contractual Life in Years	'8 years 6 months
Weighted-Average Exercise Price (in dollars per Share)	$26.17
Options Exercisable	'
Number Outstanding at the end of the period (in shares)	164
Weighted-Average Exercise Price (in dollar per Share)	$29.49

StockBased_Compensation_Detail2

Stock-Based Compensation (Details 3) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	31-May-14	31-May-13	31-May-12
Restricted stock	'	'	'
Restricted Stock	'	'	'
Compensation expense	$4.90	$7.60	$8.40
Number of Shares	'	'	'
Nonvested at the beginning of the period ( in shares)	1,253,000	'	'
Granted (in shares)	167,000	'	'
Vested (in shares)	-400,000	'	'
Forfeited (in shares)	-30,000	'	'
Nonvested at the end of the period (in shares)	990,000	1,253,000	'
Weighted Average Fair Value on Grant Date	'	'	'
Nonvested at the beginning of the period (in dollars per share)	$22.91	'	'
Granted (in dollars per share)	$24.15	'	'
Vested (in dollars per share)	$24.36	'	'
Forfeited (in dollars per share)	$27.65	'	'
Nonvested at the end of the period (in dollars per share)	$22.49	$22.91	'
Unearned compensation not yet recognized	$6.50	'	'
Average remaining amortization period of unearned compensation	'1 year 4 months 24 days	'	'
Performance-based restricted stock | Executives and other key employees	'	'	'
Number of Shares	'	'	'
Granted (in shares)	60,808	53,280	362,500
Time-based restricted stock | Board of Directors	'	'	'
Number of Shares	'	'	'
Granted (in shares)	45,000	48,333	45,000
Time-based restricted stock | Executives and other key employees	'	'	'
Number of Shares	'	'	'
Granted (in shares)	60,808	65,780	299,491

StockBased_Compensation_Detail3

Stock-Based Compensation (Details 4) (Shareholders' Rights Plan, USD $)	12 Months Ended
	31-May-14
Shareholders' Rights Plan	'
Shareholders' Rights Plan	'
Right to purchase number of shares	1
Purchase price per share (in dollars per share)	$140
Minimum percentage of the common stock shares acquired by a person or group of persons before rights become exercisable	15.00%
Market values of shares under the right (in dollars per share)	$280
Market values of shares under the right, as multiplier of exercise price	2
Minimum percentage of assets or earning power sold before rights become exercisable	50.00%
Redemption price per Right (in dollars per share)	$0.01

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Current:	'	'	'
Federal	($0.50)	($13.10)	($9.80)
State	0.2	-1.8	-0.5
Foreign	22.8	12.1	3
Total current	22.5	-2.8	-7.3
Deferred	9.6	29.5	32.8
Provision for income taxes	32.1	26.7	25.5
Income tax receivable	14.8	18	'
U.S. federal statutory income tax rate (as a percent)	35.00%	35.00%	35.00%
Reasons for difference between the provision for income taxes on pre-tax income from the amount computed by applying the U.S. federal statutory tax rate	'	'	'
Provision for income taxes at the federal statutory rate	36.9	28.8	32.7
State income taxes, net of federal benefit and refunds	0.2	-1	-3.5
Federal adjustments	-2.2	'	-3.3
Domestic Production Activities Deduction	-1.6	'	'
Research and development credit	-1	-1.1	-0.8
Noncontrolling interest	-0.1	-0.2	-0.1
Other	-0.1	0.2	0.5
Provision for income taxes	32.1	26.7	25.5
Deferred tax assets-current attributable to:	'	'	'
Inventory costs	14.4	14.8	'
Employee benefits	7.9	8.3	'
Allowance for doubtful accounts	0.8	1.6	'
Advanced billings and other	7	-6.7	'
Total net deferred tax assets-current	30.1	18	'
Deferred tax assets-noncurrent attributable to:	'	'	'
Postretirement benefits	17.6	17.7	'
Bond hedge	0.8	1.7	'
Foreign intangible assets	37.5	41.5	'
AMT, NOL and FTC carrybacks	20.6	37.6	'
Other	3	1	'
Total deferred tax assets-noncurrent	79.5	99.5	'
Total deferred tax assets	109.6	117.5	'
Deferred tax liabilities attributable to:	'	'	'
Depreciation	-166.9	-163.5	'
Convertible notes	-2.1	-3.9	'
Capitalized program development costs	-34.1	-28.8	'
Foreign intangible assets	-37.5	-41.5	'
Other	-1.1	'	'
Total deferred tax liabilities	-241.7	-237.7	'
Net deferred tax liabilities	-132.1	-120.2	'
Effective income tax rate (as a percent)	30.50%	32.50%	27.20%
Reduction in income tax expense related to tax provision to federal income tax return filing differences	2.7	'	'
Domestic Production Activities Deduction	-1.6	'	'
Reduction in income tax expense related to reduction of the entity's state income tax rate	'	$1.30	$4

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	31-May-14	31-May-13	31-May-12
Earnings Per Share	'	'	'
Effect to the participating securities as result of net loss	$0	'	'
Basic EPS:	'	'	'
Net income attributable to AAR and noncontrolling interest	73.2	55.5	68
Less income attributable to participating shares	-1.5	-2	-2.5
Less income attributable to noncontrolling interest	-0.3	-0.5	-0.3
Net income attributable to AAR available to common shareholders	71.4	53	65.2
Basic shares:	'	'	'
Weighted average common shares outstanding	38,600,000	38,300,000	38,800,000
Earnings per share - basic:	'	'	'
Earnings per share - basic (in dollars per share)	$1.85	$1.38	$1.68
Diluted EPS:	'	'	'
Net income attributable to AAR and noncontrolling interest	73.2	55.5	68
Less income attributable to participating shares	-1.5	-1.9	-2.3
Less income attributable to noncontrolling interest	-0.3	-0.5	-0.3
Add after-tax interest on convertible debt	'	3.2	5.8
Net income attributable to AAR available to common shareholders	$71.40	$56.30	$71.20
Diluted shares:	'	'	'
Weighted average common shares outstanding	38,600,000	38,300,000	38,800,000
Additional shares from the assumed exercise of stock options	500,000	100,000	200,000
Additional shares from the assumed conversion of convertible debt	'	2,200,000	4,100,000
Weighted average common shares outstanding - diluted	39,100,000	40,600,000	43,100,000
Earnings per share - diluted:	'	'	'
Earnings per share - diluted (in dollars per share)	$1.83	$1.38	$1.65
Antidilutive stock options excluded from the computation of diluted earnings per share (in shares)	180,000	872,200	1,627,000

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Amounts recognized in the consolidated balance sheets	'	'	'
Accumulated other comprehensive loss into earnings	$2.10	'	'
Unrealized losses recorded in accumulated other comprehensive loss	3.6	'	'
Cash balance pension plan	'	'	'
Employee benefit plans	'	'	'
Interest crediting rate as a percentage of average 30-year treasury rate	100.00%	'	'
Average period of treasury rate used in determination of interest crediting rate	'30 years	'	'
Average interest crediting rate (as a percent)	4.50%	'	'
Defined Benefit Pension Plans	'	'	'
Change in projected benefit obligation:	'	'	'
Projected benefit obligation at beginning of year	130.2	123	'
Service cost	2.2	2	1.6
Interest cost	5.1	5	5.5
Participant contributions	0.4	0.4	'
Net actuarial loss	5.7	3.4	'
Benefit payments	-5.1	-5.8	'
Plan change	0.6	'	'
Foreign currency adjustment	2.8	2.2	'
Projected benefit obligation at end of year	141.9	130.2	123
Reconciliation of pension assets measured at fair value	'	'	'
Fair value of plan assets at beginning of year	101.6	87.7	'
Actual return on plan assets	10.5	12.9	'
Employer contributions	6.2	4.5	'
Participant contributions	0.4	0.4	'
Benefit payments	-5.1	-5.8	'
Foreign currency adjustment	2.4	1.9	'
Fair value of plan assets at end of year	116	101.6	87.7
Funded status at end of year	-25.9	-28.6	'
Amounts recognized in the consolidated balance sheets	'	'	'
Accrued liabilities	-3.4	-3.2	'
Other liabilities and deferred income	-22.5	-25.4	'
Funded status at end of year	-25.9	-28.6	'
Amounts recognized in accumulated other comprehensive loss	'	'	'
Tax on amounts recognized in accumulated other comprehensive loss	18.4	18.8	'
Actuarial loss	35	33.9	'
Prior service cost	1.1	0.7	'
Total	36.1	34.6	'
Projected benefit obligation in excess of plan assets	'	'	'
Projected benefit obligation	141.9	130.2	'
Fair value of plan assets	116	101.6	'
Accumulated benefit obligation in excess of plan assets	'	'	'
Projected benefit obligation	85.3	83.8	'
Accumulated benefit obligation	84.8	83.4	'
Fair value of plan assets	63.3	57.5	'
Accumulated benefit obligation	134.4	124.7	'
Net Periodic Benefit Cost	'	'	'
Service cost	2.2	2	1.6
Interest cost	5.1	5	5.5
Expected return on plan assets	-5.8	-6	-6.6
Amortization of prior service cost	0.1	0.2	0.2
Recognized net actuarial loss	2	1.9	1
Total	3.6	3.1	1.7
Estimated amounts that will be amortized from accumulated other comprehensive loss into expense over the next fiscal year	'	'	'
Net actuarial loss	2	'	'
Prior service cost	0.2	'	'
Total	$2.20	'	'
Defined Benefit Pension Plans | Outside directors	'	'	'
Employee benefit plans	'	'	'
Benefits paid in cash as percentage of the annual retainer fees payable to active outside director	25.00%	'	'
Defined Benefit Pension Plans | Minimum | Outside directors	'	'	'
Employee benefit plans	'	'	'
Minimum age of retirement	'65 years	'	'
Required minimum years of service as a director	'5 years	'	'
Defined Benefit Pension Plans | Maximum | Outside directors	'	'	'
Employee benefit plans	'	'	'
Period for which benefits will be payable	'10 years	'	'
Domestic plans	'	'	'
Key weighted-average assumptions used in the measurement of the company's projected benefit obligations	'	'	'
Discount rate (as a percent)	4.20%	4.30%	'
Rate of compensation increase (as a percent)	2.50%	2.50%	'
Weighted-average assumptions used to determine net periodic pension expense	'	'	'
Discount rate (as a percent)	4.30%	4.10%	5.30%
Rate of compensation increase (as a percent)	2.50%	2.50%	3.50%
Expected long-term rate on plan assets (as a percent)	7.50%	8.00%	8.00%
Plan Assets	'	'	'
Actual asset allocation (as a percent)	100.00%	100.00%	'
Domestic plans | Equity securities	'	'	'
Plan Assets	'	'	'
Actual asset allocation (as a percent)	64.00%	61.00%	'
Domestic plans | Fixed income securities	'	'	'
Plan Assets	'	'	'
Actual asset allocation (as a percent)	17.00%	20.00%	'
Domestic plans | Other	'	'	'
Plan Assets	'	'	'
Actual asset allocation (as a percent)	19.00%	19.00%	'
Domestic plans | Minimum | Equity securities	'	'	'
Plan Assets	'	'	'
Target Asset Allocation (as a percent)	45.00%	'	'
Domestic plans | Minimum | Fixed income securities	'	'	'
Plan Assets	'	'	'
Target Asset Allocation (as a percent)	15.00%	'	'
Domestic plans | Minimum | Other	'	'	'
Plan Assets	'	'	'
Target Asset Allocation (as a percent)	0.00%	'	'
Domestic plans | Maximum | Equity securities	'	'	'
Plan Assets	'	'	'
Target Asset Allocation (as a percent)	75.00%	'	'
Domestic plans | Maximum | Fixed income securities	'	'	'
Plan Assets	'	'	'
Target Asset Allocation (as a percent)	25.00%	'	'
Domestic plans | Maximum | Other	'	'	'
Plan Assets	'	'	'
Target Asset Allocation (as a percent)	25.00%	'	'
International plans	'	'	'
Key weighted-average assumptions used in the measurement of the company's projected benefit obligations	'	'	'
Discount rate (as a percent)	3.20%	3.70%	'
Rate of compensation increase (as a percent)	3.00%	3.00%	'
Weighted-average assumptions used to determine net periodic pension expense	'	'	'
Discount rate (as a percent)	3.70%	4.10%	5.50%
Rate of compensation increase (as a percent)	3.00%	3.00%	3.00%
Expected long-term rate on plan assets (as a percent)	3.70%	4.20%	5.80%

Employee_Benefit_Plans_Details1

Employee Benefit Plans (Details 2) (Defined Benefit Pension Plans, USD $)

31-May-14

31-May-13

31-May-12

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

31-May-14

31-May-13

In Millions, unless otherwise specified

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Quoted prices in active markets (Level 1)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other observable inputs (Level 2)

Significant other unobservable inputs (Level 3)

Significant other unobservable inputs (Level 3)

Significant other unobservable inputs (Level 3)

Significant other unobservable inputs (Level 3)

Significant other unobservable inputs (Level 3)

Significant other unobservable inputs (Level 3)

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

Total

U.S. common stock

U.S. common stock

U.S. mutual funds

U.S. mutual funds

International common stock

International common stock

International mutual funds

International mutual funds

Government securities mutual funds

Government securities mutual funds

Corporate bonds mutual funds

Corporate bonds mutual funds

Cash and cash equivalents

Cash and cash equivalents

Funds-of-funds

Funds-of-funds

Hedge funds

Hedge funds

Funds-of-funds

Funds-of-funds

U.S. common stock

U.S. common stock

U.S. mutual funds

U.S. mutual funds

International common stock

International common stock

International mutual funds

International mutual funds

Government securities mutual funds

Government securities mutual funds

Corporate bonds mutual funds

Corporate bonds mutual funds

Hedge funds

Hedge funds

Funds-of-funds

Funds-of-funds

Cash and cash equivalents

Cash and cash equivalents

Employee benefit plans

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Fair value of plan assets

$116

$101.60

$87.70

$54.30

$47.40

$6.50

$6.10

$24

$21.70

$0.60

$0.70

$9.10

$6.70

$7.40

$7.20

$3.60

$4

$3.10

$1

$50.60

$44.10

$50.60

$44.10

$11.10

$10.10

$3.60

$2.40

$7.50

$7.70

$116

$101.60

$6.50

$6.10

$24

$21.70

$0.60

$0.70

$9.10

$6.70

$7.40

$7.20

$3.60

$4

$3.60

$2.40

$58.10

$51.80

$3.10

$1

Reconciliation of pension assets measured at fair value

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Fair value of plan assets at beginning of year

116

101.6

87.7

54.3

47.4

6.5

6.1

24

21.7

0.6

0.7

9.1

6.7

7.4

7.2

3.6

4

3.1

1

50.6

44.1

50.6

44.1

10.1

9.4

2.4

2.3

7.7

7.1

116

101.6

6.5

6.1

24

21.7

0.6

0.7

9.1

6.7

7.4

7.2

3.6

4

3.6

2.4

58.1

51.8

3.1

1

Sales

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-4.7

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-2.4

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-2.3

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Purchases

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5.4

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3.6

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Return on plan assets related to:

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Assets sold

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-0.3

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-0.3

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Relating to assets still held at reporting date

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0.6

0.7

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0.1

0.6

0.6

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Fair value of plan assets at end of year

$116

$101.60

$87.70

$54.30

$47.40

$6.50

$6.10

$24

$21.70

$0.60

$0.70

$9.10

$6.70

$7.40

$7.20

$3.60

$4

$3.10

$1

$50.60

$44.10

$50.60

$44.10

$11.10

$10.10

$3.60

$2.40

$7.50

$7.70

$116

$101.60

$6.50

$6.10

$24

$21.70

$0.60

$0.70

$9.10

$6.70

$7.40

$7.20

$3.60

$4

$3.60

$2.40

$58.10

$51.80

$3.10

$1

Employee_Benefit_Plans_Details2

Employee Benefit Plans (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Defined Contribution Plan	'	'	'
Vesting period	'3 years	'	'
Expense charged to statement of income	$12.50	$14	$13.20
Maximum	'	'	'
Defined Contribution Plan	'	'	'
Maximum percentage of pretax compensation that can be contributed by employees' for 401 (k) defined contribution plan	75.00%	'	'
Maximum matching contribution of employer for 401 (k) defined contribution plan (as a percent)	5.00%	'	'
Defined Benefit Pension Plans	'	'	'
Estimated future pension payments	'	'	'
2015	10.3	'	'
2016	5.7	'	'
2017	5.5	'	'
2018	6.2	'	'
2019	5.9	'	'
2020 to 2024	33.5	'	'
Funded status	'	'	'
Unfunded projected benefit obligation	25.9	28.6	'
Domestic plans	'	'	'
Estimated future pension payments	'	'	'
Anticipated contribution in next fiscal year	7.9	'	'
Postretirement Benefits Other Than Pensions	'	'	'
Funded status	'	'	'
Unfunded projected benefit obligation	$0.90	$1	'

Acquisitions_Details

Acquisitions (Details) (USD $)	0 Months Ended		3 Months Ended			0 Months Ended	1 Months Ended	3 Months Ended
In Millions, unless otherwise specified	Dec. 16, 2013	Dec. 02, 2011	Nov. 30, 2012	Aug. 31, 2012	31-May-12	Oct. 11, 2011	Oct. 31, 2011	Feb. 28, 2013	31-May-12	Aug. 31, 2012	Feb. 29, 2012
	PFW Aerospace GmbH	Telair and Nordisk	Telair and Nordisk	Telair and Nordisk	Telair and Nordisk	Airinmar	Airinmar	Airinmar	Airinmar	Airinmar	Airinmar
Acquisitions	'	'	'	'	'	'	'	'	'	'	'
Purchase price of the acquisition	$15.30	$280	'	'	$296.50	$43.50	'	'	'	'	'
Working capital adjustment paid	'	'	'	16.5	'	'	23.2	'	'	'	'
Potential earn-out payment	'	'	'	'	'	20.3	'	'	'	'	'
Period over which EBITDA levels will be measured	'	'	'	'	'	'	'2 years	'	'	'	'
Estimated liability of the acquisition date fair value of the earn-out	'	'	'	'	'	'	'	'	'	'	20.3
Reduction in liability of the acquisition date fair value of the earn-out	'	'	'	'	'	'	'	9	3.4	'	'
Adjustment amount between goodwill and identified intangibles	'	'	11	'	'	'	'	'	'	'	'
Settlement amount for the earn-out	'	'	'	'	'	'	'	4.6	'	'	'
Purchase price allocation	'	'	'	'	'	'	'	'	'	'	'
Cash	'	'	1.5	'	'	'	'	'	'	3.7	'
Accounts receivable	'	'	47.1	'	'	'	'	'	'	8	'
Inventories	4.2	'	54.5	'	'	'	'	'	'	'	'
Prepaid expenses	'	'	4.1	'	'	'	'	'	'	0.9	'
Property, plant and equipment	'	'	17	'	'	'	'	'	'	0.6	'
Deferred tax assets	'	'	34.3	'	'	'	'	'	'	5.3	'
Goodwill	0.3	'	103.9	'	'	'	'	'	'	21.6	'
Identified intangibles	10.8	'	120	'	'	'	'	'	'	20.8	'
Notes payable	'	'	-1.6	'	'	'	'	'	'	'	'
Accounts payable	'	'	-14.7	'	'	'	'	'	'	-6.7	'
Deferred tax liabilities	'	'	-34.3	'	'	'	'	'	'	-5.3	'
Accrued liabilities	'	'	-27.5	'	'	'	'	'	'	-5.4	'
Other long-term liabilities	'	'	($7.80)	'	'	'	'	'	'	'	'

Aircraft_Portfolio_Details

Aircraft Portfolio (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Feb. 28, 2013	Nov. 30, 2012	31-May-14	31-May-13	31-May-12
	item	item	item	item
Aircraft portfolio	'	'	'	'	'
Sales from services	'	'	$808.70	$908.80	$680.80
Aircraft | Owned Through Joint Ventures	'	'	'	'	'
Aircraft portfolio	'	'	'	'	'
Owned aircraft, number	'	'	4	4	'
Investment in joint ventures, receivable from sale of aircraft	'	'	12.2	15.3	'
Equity investments	'	'	28.7	27.5	'
Membership interest in joint ventures (as a percent)	'	'	50.00%	'	'
Sales from services	'	'	0.1	0.5	0.6
Summarized income statement information	'	'	'	'	'
Sales	'	'	10.4	115.2	45.7
Income before provision for income taxes	'	'	6.7	13.5	3.7
Number of aircraft sold by joint venture partners	10	2	'	'	'
Revenue from sale of aircraft by joint venture partners	64	13.9	'	'	'
Balance sheet information:	'	'	'	'	'
Assets	'	'	71.3	91.3	'
Debt	'	'	11.4	26.8	'
Members' capital	'	'	57.5	61.4	'
Aircraft | Wholly-Owned	'	'	'	'	'
Aircraft portfolio	'	'	'	'	'
Owned aircraft, number	'	'	2	2	'
Balance sheet information:	'	'	'	'	'
Gross carrying value	'	'	$25.30	$23	'

Aircraft_Portfolio_Details_2

Aircraft Portfolio (Details 2) (Aircraft)	31-May-14	31-May-13
	item	item
Owned Through Joint Ventures	'	'
Aircraft portfolio	'	'
Owned aircraft, number	4	4
Owned Through Joint Ventures | Aircraft Type 767-300 | Year Manufactured (FY) 1991 | United Airlines | Lease Expiration Date (FY) 2016 and 2017	'	'
Aircraft portfolio	'	'
Owned aircraft, number	2	'
Owned Through Joint Ventures | Aircraft Type 737-400 | Year Manufactured (FY) 1993 | City Airways | Lease Expiration Date (FY) 2018	'	'
Aircraft portfolio	'	'
Owned aircraft, number	1	'
Owned Through Joint Ventures | Aircraft Type 737-400 | Year Manufactured (FY) 1997	'	'
Aircraft portfolio	'	'
Owned aircraft, number	1	'
Wholly-Owned	'	'
Aircraft portfolio	'	'
Owned aircraft, number	2	2
Wholly-Owned | Aircraft Type 737-300 | Year Manufactured (FY) 1997 | Small Planet Airlines | Lease Expiration Date (FY) 2015	'	'
Aircraft portfolio	'	'
Owned aircraft, number	1	'
Wholly-Owned | Aircraft Type A320 | Year Manufactured (FY) 1997 | Smartlynx | Lease Expiration Date (FY) 2019	'	'
Aircraft portfolio	'	'
Owned aircraft, number	1	'

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (Garden City lease, USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 03, 2003	31-May-14	31-May-13
Garden City lease	'	'	'
Sale-leaseback transaction	'	'	'
Net proceeds from sale of facility	$14	'	'
Cost of the facility	9.5	'	'
Accumulated depreciation of the facility	4.6	'	'
Deferred gain realized on the sale	9.1	'	'
Deferred gain amortization period	'20 years	'	'
Unamortized balance of the deferred gain	'	$4.30	$4.80

Commitments_and_Contingencies_2

Commitments and Contingencies (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Aggregate amount of purchase obligations due in each of the next five fiscal years	'	'	'
2015	$236.40	'	'
2016	21.6	'	'
2017	0.6	'	'
2018	0	'	'
2019	0	'	'
Letters of credit and performance bonds outstanding	14.8	'	'
Facilities and Equipment	'	'	'
Future minimum payments under operating leases	'	'	'
2015	27.1	'	'
2016	19.3	'	'
2017	13.3	'	'
2018	10.9	'	'
2019	9.3	'	'
2020 and thereafter	29.3	'	'
Rental expense	'	'	'
Rental expense, net	$36.40	$35.20	$30.30

Other_Noncurrent_Assets_Detail

Other Noncurrent Assets (Details) (USD $)	31-May-14	31-May-13
In Millions, unless otherwise specified
Other Noncurrent Assets	'	'
Assets under deferred compensation plan	$23.70	$20.70
Cash surrender value of life insurance	17.3	16.5
License fees	13	14.7
Costs in excess of billings	15.1	9.9
Debt issuance costs	9.6	11.9
Notes receivable	5.2	16.8
Other	16.2	16.2
Other Noncurrent Assets	$100.10	$106.70

Other_Noncurrent_Assets_Detail1

Other Noncurrent Assets (Details 2) (USD $)	31-May-14	31-May-13	Jun. 30, 2011	31-May-14	31-May-14	31-May-13
In Millions, unless otherwise specified			Exclusive distribution rights	Exclusive distribution rights	License	License
			Unison Industries	Unison Industries	Unison Industries	Unison Industries
Intangible assets	'	'	'	'	'	'
Term of agreement	'	'	'10 years	'	'	'
Amount agreed to be paid	'	'	$20	'	'	'
Amount paid	'	'	7	'	'	'
Amount payable in each calendar year	'	'	'	1.3	'	'
License fees	13	14.7	'	'	11.9	13.5
Amortization period	'	'	'	'	'10 years	'
Current portion of the deferred payments	'	'	'	'	1.3	'
Long-term portion	'	'	'	'	$5.90	'

Program_Development_Costs_Deta

Program Development Costs (Details) (USD $)	31-May-14	31-May-13
In Millions, unless otherwise specified
Program Development Costs	'	'
Expected revenue from cargo loading system program	$300	'
Net costs capitalized associated with the engineering and development of the cargo system, current and noncurrent	139.8	130.9
Net costs capitalized associated with the engineering and development of the cargo system, current	27.6	6
Net costs capitalized associated with the engineering and development of the cargo system, non-current	$112.20	$124.90

Business_Segment_Information_D

Business Segment Information (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	31-May-14	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	31-May-13	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	31-May-14	31-May-13	31-May-12
									item
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Number of business segments	'	'	'	'	'	'	'	'	2	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Net sales	$505.40	$474.40	$540.70	$514.50	$553.80	$520.20	$512.80	$550.50	$2,035	$2,137.30	$2,065
Gross Profit	85.8	78.7	91	84.7	60.3	76.2	87.4	90.3	340.2	314.2	318.6
Total assets	2,199.50	'	'	'	2,136.90	'	'	'	2,199.50	2,136.90	2,195.70
Capital expenditures	'	'	'	'	'	'	'	'	26.5	37.6	91.2
Depreciation and amortization, including depreciation and amortization of stock-based compensation	'	'	'	'	'	'	'	'	89.1	90.8	84.5
Aviation Services	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1,560	1,614.40	1,536
Gross Profit	'	'	'	'	'	'	'	'	258.9	227.5	237.3
Total assets	1,266.90	'	'	'	1,262.80	'	'	'	1,266.90	1,262.80	1,360.10
Capital expenditures	'	'	'	'	'	'	'	'	17.8	28.8	77.5
Depreciation and amortization, including depreciation and amortization of stock-based compensation	'	'	'	'	'	'	'	'	57.4	59.5	56
Technology Products	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	475	522.9	529
Gross Profit	'	'	'	'	'	'	'	'	81.3	86.7	81.3
Total assets	751.5	'	'	'	716.6	'	'	'	751.5	716.6	675.4
Capital expenditures	'	'	'	'	'	'	'	'	6.4	7.7	12.3
Depreciation and amortization, including depreciation and amortization of stock-based compensation	'	'	'	'	'	'	'	'	21.1	19.6	15.7
Corporate	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Total assets	181.1	'	'	'	157.5	'	'	'	181.1	157.5	160.2
Capital expenditures	'	'	'	'	'	'	'	'	2.3	1.1	1.4
Depreciation and amortization, including depreciation and amortization of stock-based compensation	'	'	'	'	'	'	'	'	$10.60	$11.70	$12.80

Business_Segment_Information_D1

Business Segment Information (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	31-May-14	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	31-May-13	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	31-May-14	31-May-13	31-May-12
Reconciliation of segment gross profit to consolidated income before provision for income taxes	'	'	'	'	'	'	'	'	'	'	'
Segment gross profit	$85.80	$78.70	$91	$84.70	$60.30	$76.20	$87.40	$90.30	$340.20	$314.20	$318.60
Selling, general and administrative	'	'	'	'	'	'	'	'	-197.6	-198.4	-189.4
Earnings from joint ventures	'	'	'	'	'	'	'	'	3.1	6.8	1.5
Loss on extinguishment of debt	'	'	'	'	'	'	'	'	'	-0.3	-0.7
Interest expense	'	'	'	'	'	'	'	'	-42	-41.6	-37.7
Interest income	'	'	'	'	'	'	'	'	1.6	1.5	1.2
Income before provision for income taxes	'	'	'	'	'	'	'	'	$105.30	$82.20	$93.50

Business_Segment_Information_D2

Business Segment Information (Details 3) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	31-May-14	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	31-May-13	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	31-May-14	31-May-13	31-May-12
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	$505.40	$474.40	$540.70	$514.50	$553.80	$520.20	$512.80	$550.50	$2,035	$2,137.30	$2,065
U.S. Department of Defense, other U.S. government agencies and their contractors	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	694.9	763.2	888.5
Percentage of total sales	'	'	'	'	'	'	'	'	34.10%	35.70%	43.00%
Aviation Services	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	1,560	1,614.40	1,536
Aviation Services | U.S. Department of Defense, other U.S. government agencies and their contractors	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	521.3	548.2	534.9
Technology Products	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	475	522.9	529
Technology Products | U.S. Department of Defense, other U.S. government agencies and their contractors	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	$173.60	$215	$353.60

Business_Segment_Information_D3

Business Segment Information (Details 4) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	31-May-14	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	31-May-13	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	31-May-14	31-May-13	31-May-12
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Long-lived assets	$1,082.60	'	'	'	$1,103.20	'	'	'	$1,082.60	$1,103.20	'
Sales	505.4	474.4	540.7	514.5	553.8	520.2	512.8	550.5	2,035	2,137.30	2,065
United States	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Long-lived assets	809	'	'	'	834.1	'	'	'	809	834.1	'
Europe	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Long-lived assets	271.4	'	'	'	267.2	'	'	'	271.4	267.2	'
Other	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Long-lived assets	2.2	'	'	'	1.9	'	'	'	2.2	1.9	'
Foreign countries	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Sales	'	'	'	'	'	'	'	'	$668.40	$656.50	$435.70
Foreign countries | Total sales | Geographic concentration	'	'	'	'	'	'	'	'	'	'	'
Business Segment Information	'	'	'	'	'	'	'	'	'	'	'
Percentage of total sales	'	'	'	'	'	'	'	'	32.80%	30.70%	21.10%

Selected_Quarterly_Data_Unaudi2

Selected Quarterly Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	31-May-14	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	31-May-13	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	31-May-14	31-May-13	31-May-12
Selected Quarterly Data (Unaudited)	'	'	'	'	'	'	'	'	'	'	'
Sales	$505.40	$474.40	$540.70	$514.50	$553.80	$520.20	$512.80	$550.50	$2,035	$2,137.30	$2,065
Gross Profit	85.8	78.7	91	84.7	60.3	76.2	87.4	90.3	340.2	314.2	318.6
Net income attributable to AAR	$17.10	$17.90	$20	$17.90	$0.60	$18.40	$17.80	$18.20	$72.90	$55	$67.70
Diluted earnings per share (in dollars per share)	$0.43	$0.45	$0.50	$0.45	$0.01	$0.46	$0.44	$0.45	$1.83	$1.38	'
Dividends declared (in dollars per share)	$0.08	$0.08	$0.08	$0.08	$0.08	$0.08	$0.08	$0.08	$0.30	$0.30	'
High Market Price (in dollars per share)	$31.05	$30.56	$31.30	$25.84	$20.47	$20.11	$17.17	$14.88	$31.30	$20.47	'
Low Market Price (in dollars per share)	$24.22	$25.91	$25.51	$20.06	$16.47	$15.13	$13.55	$10.34	$20.06	$10.34	'

Allowance_for_Doubtful_Account2

Allowance for Doubtful Accounts (Details) (Allowance for Doubtful Accounts, USD $)	12 Months Ended
In Millions, unless otherwise specified	31-May-14	31-May-13	31-May-12
Allowance for Doubtful Accounts	'	'	'
Changes in allowance for doubtful accounts	'	'	'
Balance, beginning of year	$8.70	$6.50	$5.70
Provision charged to operations	0.7	6.8	2.4
Deductions for accounts written off, net of recoveries	-3.2	-4.6	-1.6
Balance, end of year	$6.20	$8.70	$6.50