CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Revenue	$ 106,533	$ 102,122
Cost of goods sold	56,494	52,843
Gross profit	50,039	49,279
Operating expenses:
Research, development and technical	15,316	13,755
Selling and marketing	7,109	7,336
General and administrative	10,954	12,901
Total operating expenses	33,379	33,992
Operating income	16,660	15,287
Interest expense	953	39
Other income (expense), net	854	104
Income before income taxes	16,561	15,352
Provision for income taxes	6,858	4,937
Net income	$ 9,703	$ 10,415
Basic earnings per share	$ 0.42	$ 0.46
Weighted average basic shares outstanding	22,845	22,508
Diluted earnings per share	$ 0.41	$ 0.45
Weighted average diluted shares outstanding	23,658	22,926