Segment and Geographic Information (Details) (USD $) In Thousands, 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
Summarize the companies segment information
Net sales	$ 36,949	$ 55,201	$ 56,233	$ 43,281	$ 32,805	$ 46,368	$ 50,696	$ 43,101	$ 191,664	$ 172,970	$ 128,533
Total income (loss) from operations	6,194	15,601	16,472	12,598	6,049	13,511	13,048	11,797	50,865	44,405	21,108
Total Depreciation, amortization and stock-based compensation									10,349	7,783	5,629
Total interest income									743	267	254
Total interest expense									199	43	238
Seismic [Member]
Summarize the companies segment information
Net sales									178,221	158,653	114,774
Total income (loss) from operations									59,455	53,477	28,955
Total Depreciation, amortization and stock-based compensation									8,533	5,990	3,995
Total interest income									581	139	165
Total interest expense									199
Thermal Solutions [Member]
Summarize the companies segment information
Net sales									12,642	13,519	12,955
Total income (loss) from operations									1,014	(37)	397
Total Depreciation, amortization and stock-based compensation									320	345	375
Total interest income									5
Total interest expense
Corporate [Member]
Summarize the companies segment information
Net sales									801	798	804
Total income (loss) from operations									(9,604)	(9,035)	(8,244)
Total Depreciation, amortization and stock-based compensation									1,496	1,448	1,259
Total interest income									157	128	89
Total interest expense										$ 43	$ 238