Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Company's segment information
Total	$ 55,201	$ 46,368	$ 154,715	$ 140,165
Total	15,601	13,511	44,671	38,356
Seismic [Member]
Company's segment information
Total	51,708	42,769	144,576	129,396
Total	17,713	15,772	51,262	45,497
Thermal Solutions [Member]
Company's segment information
Total	3,293	3,396	9,538	10,172
Total	273	(287)	720	(196)
Corporate [Member]
Company's segment information
Total	200	203	601	597
Total	$ (2,385)	$ (1,974)	$ (7,311)	$ (6,945)