Quarterly Results Of Operations (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2011
Disclosure - Quarterly Results Of Operations (Details) [Line Items]
Revenues	$ 187,397		$ 179,519		$ 153,915		$ 153,941		$ 184,159	$ 194,093	$ 181,486	$ 157,456	$ 674,772		$ 717,194
Gross profit	42,852		38,485		31,715		33,784		41,480	43,843	34,237	20,378	146,836		139,938	99,930
Net income (loss)	$ 18,568		$ 9,305		$ 6,818		$ 7,385		$ 11,853	$ 12,138	$ 7,411	$ (1,745)	$ 42,076		$ 29,657	$ (2,715)
Earnings (loss) per share:
Basic	$ 1.55	[1]	$ 0.78	[1]	$ 0.57	[1]	$ 0.62	[1]	$ 0.99	$ 1.03	$ 0.63	$ (0.15)	$ 3.52	[1]	$ 2.50	$ (0.23)
Diluted	$ 1.54	[1]	$ 0.77	[1]	$ 0.57	[1]	$ 0.62	[1]	$ 0.99	$ 1.02	$ 0.63	$ (0.15)	$ 3.51	[1]	$ 2.49	$ (0.23)

[1] The increase in earnings per share for the fourth quarter of Fiscal 2013 was primarily driven by the release of our Canadian valuation allowance. For an explanation of the effective tax rate in Fiscal 2013, see Note H.