Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 69,557	$ 35,118	$ 29,711
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Deferred income tax expense (benefit)	(523)	808	(718)
Depreciation and amortization	12,229	9,587	7,047
Accretion of discounts on short-term-investments	162	208
Stock-based compensation	544	762	736
Bad debt expense	457	118	128
Inventory obsolescence expense	187	1,793	4,608
Gross profit from sale of used rental equipment	(13,627)	(9,992)	(11,165)
(Gain) loss on disposal of property, plant and equipment	301	(34)
Realized (gain) loss on short-term investments	(19)	1	27
Effects of changes in operating assets and liabilities:
Trade accounts and notes receivable	(33,717)	3,781	2,006
Inventories	(73,357)	(15,630)	(29,528)
Costs and estimated earnings in excess of billings	(12,400)
Prepaid expenses and other current assets	(458)	(293)	(2,539)
Prepaid income taxes	(722)	(4,500)	1,023
Accounts payable trade	(442)	12,151	1,227
Accrued expenses and other	3,324	576	787
Deferred revenue	(7,541)	7,897	(558)
Income taxes payable	(1,116)	873	(1,656)
Net cash provided by (used in) operating activities	(57,161)	43,224	1,136
Cash flows from investing activities:
Purchase of property, plant and equipment	(19,384)	(4,013)	(4,730)
Proceeds from the sale of property, plant and equipment		17	1
Investment in rental equipment	(22,275)	(31,716)	(15,414)
Proceeds from the sale of used rental equipment	25,497	24,184	19,917
Purchases of short-term investments	(1,587)	(16,823)	(4,926)
Proceeds from the sale of short-term investments	21,139	2,030
Net cash provided by (used in) investing activities	3,390	(26,321)	(5,152)
Cash flows from financing activities:
Principal payments under mortgage loans			(7,700)
Net borrowings under line of credit	931
Excess tax benefits from stock-based compensation	3,390	1,131	6,896
Proceeds from exercise of stock options and other	1,419	1,358	2,758
Net cash provided by financing activities	5,740	2,489	1,954
Effect of exchange rate changes on cash	5	(28)	(3)
Increase (decrease) in cash and cash equivalents	(48,026)	19,364	(2,065)
Cash and cash equivalents, beginning of fiscal year	50,752	31,388	33,453
Cash and cash equivalents, end of fiscal year	$ 2,726	$ 50,752	$ 31,388