Revenues from Rental, Lease and Sale Group (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Nov. 30, 2013		Nov. 30, 2012		Nov. 30, 2013		Nov. 30, 2012
Revenue from External Customer [Line Items]
Rentals and leases	$ 35,205		$ 34,575		$ 70,862		$ 68,240
Sales of equipment and other revenues	22,671		30,617		47,182		55,453
Total revenues	57,876	[1]	65,192	[1]	118,044	[1]	123,693	[1]
T&M
Revenue from External Customer [Line Items]
Rentals and leases	31,060		30,435		61,880		60,040
Sales of equipment and other revenues	22,263		29,944		46,113		54,091
Total revenues	53,323		60,379		107,993		114,131
DP
Revenue from External Customer [Line Items]
Rentals and leases	4,145		4,140		8,982		8,200
Sales of equipment and other revenues	408		673		1,069		1,362
Total revenues	$ 4,553		$ 4,813		$ 10,051		$ 9,562

[1] Revenues by country are based on the location of shipping destination, and not whether the order originates in the United States parent or a foreign subsidiary.