Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 28, 2013		Feb. 29, 2012		Feb. 28, 2013		Feb. 29, 2012
Revenues:
Rentals and leases	$ 32,837		$ 31,704		$ 101,077		$ 95,925
Sales of equipment and other revenues	31,835		28,375		87,288		84,447
Total revenues	64,672	[1]	60,079	[1]	188,365	[1]	180,372	[1]
Operating expenses:
Depreciation of rental and lease equipment	14,320		13,677		42,460		39,578
Costs of rental and lease, excluding depreciation	4,721		4,428		13,651		13,201
Costs of sales of equipment and other revenues	23,471		21,091		63,684		62,382
Selling, general and administrative expenses	13,784		13,033		41,629		39,302
Total operating expenses	56,296		52,229		161,424		154,463
Operating profit	8,376		7,850		26,941		25,909
Gain on bargain purchase, net of deferred taxes			53				3,435
Interest income, net	61		120		344		327
Income before income taxes	8,437		8,023		27,285		29,671
Income tax provision	3,400		3,028		10,923		10,152
Net income	$ 5,037		$ 4,995		$ 16,362		$ 19,519
Earnings per share:
Basic	$ 0.21		$ 0.21		$ 0.68		$ 0.81
Diluted	$ 0.21		$ 0.21		$ 0.68		$ 0.81
Shares used in per share calculation:
Basic	23,996		23,983		23,995		23,981
Diluted	24,257		24,179		24,228		24,180
Cash dividend paid per common share	$ 1.20		$ 0.20		$ 1.60		$ 0.60

[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.