Quarterly Results Of Operations (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Quarterly Results Of Operations [Abstract]
Revenues	$ 184,159	$ 194,093	$ 181,486	$ 157,456	$ 171,243	$ 141,369	$ 125,111	$ 124,674	$ 717,194	$ 562,397
Gross profit	41,480	43,843	34,237	20,378	27,324	21,864	24,877	25,865	139,938	99,930	142,057
Net income (loss)	11,853	12,138	7,411	(1,745)	(6,953)	73	1,733	2,432	29,657	(2,715)	25,008
Basic earnings (loss) per share	$ 0.99	$ 1.03	$ 0.63	$ (0.15)	$ (0.59)	$ 0.01	$ 0.15	$ 0.21	$ 2.50	$ (0.23)	$ 2.17
Diluted earnings (loss) per share	$ 0.99	$ 1.02	$ 0.63	$ (0.15)	$ (0.59)	$ 0.01	$ 0.15	$ 0.21	$ 2.49	$ (0.23)	$ 2.14
Gain on sale of investment										$ 1,229