CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 22,013	$ 8,685
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Deferred income tax expense	458	339
Depreciation	1,994	1,771
Amortization	60	60
Accretion of discounts on short-term-investments	87	36
Stock-based compensation	250	187
Bad debt expense	269	436
Inventory obsolescence recovery	(550)	(132)
Gross profit from the sale of used rental equipment	(6,519)	(2,165)
Loss on disposal of property, plant and equipment	19
Realized (gain) loss on short-term investments	(1)	1
Effects of changes in operating assets and liabilities:
Trade accounts and notes receivable	(5,981)	(2,210)
Inventories	(13,704)	7,734
Costs and estimated earnings in excess of billings	(6,325)
Other current assets	(3,823)	3,780
Prepaid income taxes	(1,231)	(3,816)
Accounts payable	154	2,508
Accrued expenses and other	152	(660)
Deferred revenue	2,112	341
Income taxes payable	8,454	3,184
Net cash provided by (used in) operating activities	(2,112)	20,079
Cash flows from investing activities:
Purchase of property, plant and equipment	(6,494)	(792)
Investment in rental equipment	(11,419)	(16,437)
Proceeds from sale of used rental equipment	12,408	3,577
Purchases of short-term investments	(702)	(675)
Proceeds from the sale of short-term investments	900	625
Net cash used in investing activities	(5,307)	(13,702)
Cash flows from financing activities:
Excess tax benefit from stock-based compensation	1,092	(3)
Proceeds from exercise of stock options and other	461	79
Net cash provided by financing activities	1,553	76
Effect of exchange rate changes on cash		1
Increase (decrease) in cash and cash equivalents	(5,866)	6,454
Cash and cash equivalents, beginning of period	50,752	31,388
Cash and cash equivalents, end of period	$ 44,886	$ 37,842