Summary of Company's Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Revenue	$ 16,008	$ 19,751	$ 27,942	$ 21,166	$ 26,285	$ 40,728	$ 68,551	$ 101,348	$ 84,867	$ 236,912	$ 300,607
Income (loss) from operations	$ (21,667)	$ (12,451)	$ (8,549)	$ (9,888)	$ (3,282)	$ 5,458	$ 15,956	$ 35,667	(52,555)	53,799	101,227
Depreciation, amortization, goodwill impairment and stock-based compensation expenses									25,929	21,893	12,773
Interest income									427	123	880
Interest expense									229	471	260
Operating Segments | Seismic
Segment Reporting Information [Line Items]
Revenue									60,565	214,946	275,201
Income (loss) from operations									(42,732)	65,159	110,118
Depreciation, amortization, goodwill impairment and stock-based compensation expenses									23,696	19,925	11,207
Interest income									280	74	781
Interest expense											141
Operating Segments | Non-Seismic
Segment Reporting Information [Line Items]
Revenue									23,758	21,420	24,578
Income (loss) from operations									3,031	2,733	3,344
Depreciation, amortization, goodwill impairment and stock-based compensation expenses									505	468	289
Interest income									7	5	2
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Revenue									544	546	828
Income (loss) from operations									(12,854)	(14,093)	(12,235)
Depreciation, amortization, goodwill impairment and stock-based compensation expenses									1,728	1,500	1,277
Interest income									140	44	97
Interest expense									$ 229	$ 471	$ 119