Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 29, 2016	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015
Condensed Consolidated Statements of Comprehensive Income
Net income (loss) attributable to AAR and noncontrolling interest	$ 4.8	$ (34.4)	$ 35.7	$ (4.7)
Other comprehensive income (loss), net of tax expense (benefit):
Currency translation adjustments, net of tax of $0 and ($0.6) for the three months ended February 29, 2016 and February 28, 2015, respectively, and $0 and $0.6 for the nine months ended February 29, 2016 and February 28, 2015, respectively	(1.8)	(26.1)	(0.8)	(49.9)
Unrealized gain (loss) on derivative instruments:
Unrealized gain (loss) arising during period, net of tax of $0 and $0.1 for the three months ended February 29, 2016 and February 28, 2015, respectively, and $0 and $0.3 for the nine months ended February 29, 2016 and February 28, 2015, respectively		0.4		0.6
Pension and other post-retirement plans:
Amortization of actuarial loss and prior service cost included in net income, net of tax of $0.1 and $0 for the three months ended February 29, 2016 and 2015, respectively, and $0.4 and $0.1 for the nine months ended February 29, 2016 and 2015, respectively	0.3	(0.2)	0.8	(0.1)
Other comprehensive income (loss), net of tax	(1.5)	(25.9)		(49.4)
Comprehensive income (loss), net of tax	3.3	(60.3)	35.7	(54.1)
Comprehensive income related to noncontrolling interest		(0.1)		(0.2)
Comprehensive income (loss) attributable to AAR	$ 3.3	$ (60.4)	$ 35.7	$ (54.3)