Consolidated Statements of Changes in Stockholders' Equity (USD $)	Total	Treasury Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance at Sep. 30, 2010	$ 112,374,000	$ (18,343,000)	$ 27,000	$ 85,517,000	$ (4,645,000)	$ 49,818,000
Balance (in shares) at Sep. 30, 2010		(1,932,481)	28,827,072
Increase (Decrease) in Stockholders' Equity
Common stock repurchase	(3,541,000)	(3,541,000)
Common stock repurchase (in shares)	(229,575)	(229,575)
Exercise of common stock options and restricted stock	23,639,000		2,000	23,637,000
Exercise of common stock options and restricted stock (in shares)			2,365,536
Compensation expense and incremental tax benefit from grant of common stock options and restricted stock	15,732,000			15,732,000
Comprehensive income:
Net income	8,512,000					8,512,000
Foreign currency translation and other	4,697,000				4,697,000
Balance at Sep. 30, 2011	161,413,000	(21,884,000)	29,000	124,886,000	52,000	58,330,000
Balance (in shares) at Sep. 30, 2011		(2,162,056)	31,192,608
Increase (Decrease) in Stockholders' Equity
Common stock repurchase	(29,999,000)	(29,999,000)
Common stock repurchase (in shares)		(505,067)
Common stock retired		51,883,000		(11,622,000)		(40,261,000)
Common stock retired (in shares)		2,667,123	(2,667,123)
Exercise of common stock options and restricted stock	15,491,000		1,000	15,490,000
Exercise of common stock options and restricted stock (in shares)			1,712,455
Stock consideration paid for acquisition	24,538,000		1,000	24,537,000
Stock consideration paid for acquisition (in shares)			900,171
Compensation expense and incremental tax benefit from grant of common stock options and restricted stock	29,070,000			29,070,000
Comprehensive income:
Net income	48,296,000					48,296,000
Defined benefit pension plan - unrecognized amounts, net of taxes	584,000				584,000
Foreign currency translation and other	610,000				610,000
Balance at Sep. 30, 2012	250,003,000		31,000	182,361,000	1,246,000	66,365,000
Balance (in shares) at Sep. 30, 2012			31,138,111
Increase (Decrease) in Stockholders' Equity
Common stock repurchase (in shares)	0
Exercise of common stock options and restricted stock	2,532,000			2,532,000
Exercise of common stock options and restricted stock (in shares)			673,653
Compensation expense and incremental tax benefit from grant of common stock options and restricted stock	21,968,000			21,968,000
Comprehensive income:
Net income	41,104,000					41,104,000
Defined benefit pension plan - unrecognized amounts, net of taxes	563,000				563,000
Foreign currency translation and other	(1,291,000)				(1,291,000)
Balance at Sep. 30, 2013	$ 314,879,000		$ 31,000	$ 206,861,000	$ 518,000	$ 107,469,000
Balance (in shares) at Sep. 30, 2013			31,811,764