CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 34,992	$ 38,882
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Deferred income tax (benefit) expense	(676)	1,084
Depreciation	8,662	5,857
Amortization		80
Accretion of discounts on short-term-investments		160
Stock-based compensation	1,935	347
Bad debt expense	644	607
Inventory obsolescence expense (recovery)	1,717	(186)
Gross profit from the sale of used rental equipment	(5,466)	(9,062)
(Gain) loss on disposal of property, plant and equipment	(58)	14
Realized gain on short-term investments		(6)
Effects of changes in operating assets and liabilities:
Trade accounts and notes receivable	337	(21,188)
Inventories	(3,987)	(31,428)
Costs and estimated earnings in excess of billings	12,400	(11,309)
Other current assets	306	(4,710)
Prepaid income taxes	(950)	(2,034)
Accounts payable	(2,496)	1,735
Accrued expenses and other	(1,346)	(2,350)
Deferred revenue	5,672	(8,461)
Income taxes payable	4,117	(587)
Net cash provided by (used in) operating activities	55,803	(42,555)
Cash flows from investing activities:
Purchase of property, plant and equipment	(4,379)	(8,244)
Investment in rental equipment	(18,309)	(17,673)
Proceeds from sale of used rental equipment	8,551	17,074
Purchases of short-term investments		(1,587)
Proceeds from the sale of short-term investments		10,672
Net cash (used in) provided by investing activities	(14,137)	242
Cash flows from financing activities:
Principal payments on debt arrangements	(931)
Excess tax benefit from stock-based compensation	661	2,948
Proceeds from exercise of stock options	212	917
Net cash (used in) provided by financing activities	(58)	3,865
Effect of exchange rate changes on cash	6	4
Increase (decrease) in cash and cash equivalents	41,614	(38,444)
Cash and cash equivalents, beginning of period	2,726	50,752
Cash and cash equivalents, end of period	$ 44,340	$ 12,308