Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 35,118	$ 29,711	$ 14,082
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax expense (benefit)	808	(718)	(1,416)
Depreciation	9,348	6,769	4,921
Amortization	239	278	263
Accretion of discounts on short-term-investments	208
Stock-based compensation	762	736	445
Bad debt expense (recovery)	118	128	(479)
Inventory obsolescence expense	1,793	4,608	2,872
Gross profit from the sale of used rental equipment	(9,992)	(11,165)	(385)
Loss on early extinguishment of debt			137
(Gain) loss on disposal of property, plant and equipment	(34)		184
Realized loss on short-term investments	1	27
Effects of changes in operating assets and liabilities:
Trade accounts and notes receivable	3,781	2,006	(2,678)
Inventories	(15,630)	(29,528)	6,673
Other current assets	(293)	(2,539)	(855)
Accounts payable	12,151	1,227	(879)
Accrued expenses and other	576	787	4,157
Deferred revenue	7,897	(558)	948
Income taxes payable	873	(1,656)	1,898
Prepaid income taxes	(4,500)	1,023	(1,110)
Net cash provided by operating activities	43,224	1,136	28,778
Cash flows from investing activities:
Purchase of property, plant and equipment	(4,013)	(4,730)	(2,224)
Proceeds from the sale of property, plant and equipment	17	1	11
Investment in rental equipment	(31,716)	(15,414)	(3,893)
Proceeds from the sale of used rental equipment	24,184	19,917	1,243
Purchase of short-term investments	(16,823)	(4,926)
Proceeds from the sale of short-term investments	2,030
Net cash used in investing activities	(26,321)	(5,152)	(4,863)
Cash flows from financing activities:
Principal payments under mortgage loans		(7,700)	(1,848)
Penalty for early extinguishment of debt			(137)
Excess tax benefits from stock-based compensation	1,131	6,896	1,128
Proceeds from exercise of stock options and other	1,358	2,758	2,187
Net cash provided by financing activities	2,489	1,954	1,330
Effect of exchange rate changes on cash	(28)	(3)	(363)
Increase (decrease) in cash and cash equivalents	19,364	(2,065)	24,882
Cash and cash equivalents, beginning of fiscal year	31,388	33,453	8,571
Cash and cash equivalents, end of fiscal year	$ 50,752	$ 31,388	$ 33,453