Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net income	$ 20,116	$ 16,915
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax expense (benefit)	5	(1,288)
Depreciation	4,810	3,532
Amortization	120	158
Accretion of discounts on securities available-for-sale	73
Stock-based compensation expense	376	374
Bad debt expense	604	33
Inventory obsolescence reserve	1,125	2,373
Gross profit from the sale of used rental equipment	(7,301)	(713)
Gain on disposal of property, plant and equipment		(16)
Realized loss on short-term investments	1
Effects of changes in operating assets and liabilities:
Trade accounts and notes receivable	(13,435)	(15,214)
Inventories	2,068	(14,028)
Other current assets	3,227	734
Accounts payable	6,772	10,578
Accrued expenses and other	34	(1,156)
Deferred revenue	4,674	128
Income taxes payable	2,680	1,651
Prepaid income taxes	(2,730)	1,370
Net cash provided by operating activities	23,219	5,431
Cash flows from investing activities:
Purchase of property and equipment	(1,672)	(2,907)
Proceeds from sale of property and equipment		1
Investment in rental equipment	(22,191)	(8,568)
Proceeds from sale of used rental equipment	12,451	867
Purchase of short-term investments	(1,025)
Proceeds from sale of short-term investments	950
Net cash used in investing activities	(11,487)	(10,607)
Cash flows from financing activities:
Principal payments on mortgage loans		(7,700)
Excess tax benefit from share-based compensation	425	1,688
Proceeds from exercise of stock options and other	605	1,433
Net cash provided by (used in) financing activities	1,030	(4,579)
Effect of exchange rate changes on cash		330
Increase (decrease) in cash and cash equivalents	12,762	(9,425)
Cash and cash equivalents, beginning of period	31,388	33,453
Cash and cash equivalents, end of period	$ 44,150	$ 24,028