Segment Reporting and Related Disclosures - Revenues from Rental, Lease and Sale Group (Detail) - USD ($) $ in Thousands		3 Months Ended
		Aug. 31, 2015	Aug. 31, 2014
Revenue from External Customer [Line Items]
Rentals and leases		$ 32,303	$ 33,889
Sales of equipment and other revenues		21,040	27,982
Total revenues	[1]	53,343	61,871
Depreciation		14,601	13,915
T&M | Operating Segments
Revenue from External Customer [Line Items]
Rentals and leases		27,130	29,249
Sales of equipment and other revenues		20,543	27,476
Total revenues		47,673	56,725
Depreciation		13,454	12,932
DP | Operating Segments
Revenue from External Customer [Line Items]
Rentals and leases		5,173	4,640
Sales of equipment and other revenues		497	506
Total revenues		5,670	5,146
Depreciation		$ 1,147	$ 983

[1] Revenues by country are based on the shipping destination.