Segment Reporting and Related Disclosures - Revenues from Rental, Lease and Sale Group (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Feb. 29, 2016	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015
Revenue from External Customer [Line Items]
Rentals and leases		$ 29,173	$ 30,252	$ 93,649	$ 97,610
Sales of equipment and other revenues		10,325	26,090	42,502	80,306
Total revenues	[1]	39,498	56,342	136,151	177,916
Depreciation		13,744	13,844	42,685	42,429
T&M | Operating Segments
Revenue from External Customer [Line Items]
Rentals and leases		25,340	26,372	79,937	84,410
Sales of equipment and other revenues		9,857	25,799	40,888	79,033
Total revenues		35,197	52,171	120,825	163,443
Depreciation		12,699	12,856	39,388	39,387
DP | Operating Segments
Revenue from External Customer [Line Items]
Rentals and leases		3,833	3,880	13,712	13,200
Sales of equipment and other revenues		468	291	1,614	1,273
Total revenues		4,301	4,171	15,326	14,473
Depreciation		$ 1,045	$ 988	$ 3,297	$ 3,042

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