Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2011	Nov. 30, 2010
Revenues:
Rentals and leases	$ 32,912	$ 29,673	$ 64,221	$ 58,460
Sales of equipment and other revenues	28,731	23,604	56,072	45,642
Total revenues	61,643	53,277	120,293	104,102
Operating expenses:
Depreciation of rental and lease equipment	13,374	11,919	25,901	23,575
Costs of revenues other than depreciation of rental and lease equipment	22,901	18,087	44,511	35,309
Selling, general and administrative expenses	15,929	13,714	31,822	27,282
Total operating expenses	52,204	43,720	102,234	86,166
Operating profit	9,439	9,557	18,059	17,936
Gain on bargain purchase, net of deferred taxes	188	49	3,382	202
Interest income, net	108	101	207	219
Income before income taxes	9,735	9,707	21,648	18,357
Income tax provision	3,716	2,588	7,124	6,017
Net income	$ 6,019	$ 7,119	$ 14,524	$ 12,340
Earnings per share:
Basic	$ 0.25	$ 0.30	$ 0.61	$ 0.51
Diluted	$ 0.25	$ 0.30	$ 0.60	$ 0.51
Shares used in per share calculation:
Basic	23,981	23,976	23,981	23,970
Diluted	24,149	24,075	24,139	24,049