Business Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012 item	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2013 item	May 31, 2012	May 31, 2011
Business Segment Information
Number of business segments				4					2
Business Segment Information
Net sales	$ 553.8	$ 520.2	$ 512.8	$ 550.5	$ 563.3	$ 534.2	$ 482.0	$ 485.5	$ 2,137.3	$ 2,065.0	$ 1,805.1
Gross Profit	60.3	76.2	87.4	90.3	77.4	86.9	78.6	75.7	314.2	318.6	307.1
Total assets	2,136.9				2,195.7				2,136.9	2,195.7	1,703.7
Capital expenditures									37.6	91.2	124.9
Depreciation and amortization, including depreciation and amortization of stock-based compensation									90.8	84.5	71.6
Aviation Services
Business Segment Information
Net sales									1,614.4	1,536.0	1,398.2
Gross Profit									227.5	237.3	235.5
Total assets	1,262.8				1,360.1				1,262.8	1,360.1	1,236.0
Capital expenditures									28.8	77.5	115.7
Depreciation and amortization, including depreciation and amortization of stock-based compensation									59.5	56.0	47.9
Technology Products
Business Segment Information
Net sales									522.9	529.0	406.9
Gross Profit									86.7	81.3	71.6
Total assets	716.6				675.4				716.6	675.4	326.8
Capital expenditures									7.7	12.3	6.0
Depreciation and amortization, including depreciation and amortization of stock-based compensation									19.6	15.7	10.1
Corporate
Business Segment Information
Total assets	157.5				160.2				157.5	160.2	140.9
Capital expenditures									1.1	1.4	3.2
Depreciation and amortization, including depreciation and amortization of stock-based compensation									$ 11.7	$ 12.8	$ 13.6