Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	May 31, 2012	May 31, 2011	May 31, 2010
Revenues:
Rentals and leases	$ 129,737	$ 118,062	$ 94,201
Sales of equipment and other revenues	118,817	110,667	51,666
Total revenues	248,554	228,729	145,867
Operating expenses:
Depreciation of rental and lease equipment	53,651	47,922	42,605
Costs of revenues other than depreciation of rental and lease equipment	94,856	86,649	39,061
Selling, general and administrative expenses	63,961	57,423	46,447
Total operating expenses	212,468	191,994	128,113
Operating profit	36,086	36,735	17,754
Gain on bargain purchase, net of deferred taxes	3,435	202	679
Interest income, net	484	352	1,599
Income before income taxes	40,005	37,289	20,032
Income tax provision	14,233	13,533	8,435
Net income	$ 25,772	$ 23,756	$ 11,597
Earnings per share:
Basic	$ 1.07	$ 0.99	$ 0.48
Diluted	$ 1.07	$ 0.99	$ 0.48
Shares used in per share calculation:
Basic	23,983	23,974	23,932
Diluted	24,152	24,072	24,004