Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Feb. 29, 2012	Feb. 28, 2011
Cash flows from operating activities:
Net income	$ 19,519	$ 17,417
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	40,551	36,663
Put option loss		952
Realized gain on redemption of trading securities		(952)
Remeasurement loss (gain) on foreign currency	104	(21)
Provision for losses on accounts receivable	130	446
Gain on sale of rental and lease equipment	(7,578)	(8,016)
Gain on bargain purchase, net of taxes	(3,435)	(202)
Stock compensation expense	1,057	692
Excess tax benefit for share based compensation	(89)	(33)
Deferred income taxes	7,594	20,224
Changes in operating assets and liabilities:
Accounts receivable	(1,686)	(7,408)
Other assets	(1,023)	(13,698)
Accounts payable	(1,140)	(1,298)
Accrued expenses	658	(2,349)
Deferred revenue	27	13
Net cash provided by operating activities	54,689	42,430
Cash flows from investing activities:
Proceeds from sale of rental and lease equipment	17,114	20,847
Cash paid for acquisition	(10,572)
Proceeds from acquisition purchase price adjustment		202
Payments for purchase of rental and lease equipment	(78,703)	(69,760)
Redemptions of investments, trading		14,275
Payments for purchase of other property	(642)	(723)
Net cash used in investing activities	(72,803)	(35,159)
Cash flows from financing activities:
Borrowing under bank line of credit	1,000
Payment under bank line of credit	(1,000)
Proceeds from issuance of common stock		196
Minimum tax withholdings on share based compensation	(47)
Excess tax benefit for share based compensation	89	33
Payment of dividends	(14,480)	(10,843)
Net cash used in financing activities	(14,438)	(10,614)
Net decrease in cash and cash equivalents	(32,552)	(3,343)
Effect of exchange rate changes on cash	(11)	(232)
Cash and cash equivalents at beginning of period	41,441	32,906
Cash and cash equivalents at end of period	$ 8,878	$ 29,331