Selected Quarterly Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended						12 Months Ended			15 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Sep. 30, 2012
Summary of selected quarterly information
Service revenues	$ 122,082	$ 93,023	$ 72,844	$ 66,634	$ 49,516	$ 58,165	$ 354,583	$ 265,586	$ 279,120	$ 84,011	$ 73,894
Product revenues	50,988	43,300	32,370	45,076	39,016	32,387	171,734	189,035	165,202	75,872	41,760
Revenues	173,070	136,323	105,214	111,710	88,532	90,552	526,317	454,621	444,322	159,883	115,654
Gross profit	72,744	55,958	45,943	41,156	33,631	31,139	215,801	173,445	165,733	64,617	44,058
Income from operations	24,863	25,049	12,972	11,643	8,800	6,071	74,527	66,795	52,847	33,428	18,496
Interest expense, net	(1,146)	(1,237)	(1,364)	(1,518)	(1,187)	(1,615)	(5,265)	(5,784)	(30,770)	(1,600)	(1,382)
Equity in (earnings) losses of INOVA Geophysical	(4,264)	(1,684)	3,777	2,468	(4,173)	(860)	297	(22,862)	(23,724)	(13,018)	(4,811)
Other income (expense)	17,851	(936)	895	(686)	497	(2,999)	17,124	(3,447)	(8,249)	(1,144)	199
Income tax expense	10,191	6,037	4,184	3,445	1,085	147	23,857	10,136	26,942	5,420	3,484
Net income attributable to noncontrolling interests	53	42	281	113	44	25	489	208	0	105	34
Preferred stock dividends	338	338	338	338	338	338	1,352	1,352	1,936	338	338
Net income (loss) applicable to common shares	$ 26,828	$ 14,859	$ 12,039	$ 8,237	$ 2,558	$ 137	$ 61,963	$ 23,422	$ (38,774)	$ 12,013	$ 8,714
Net income per share:
Basic	$ 0.17	$ 0.10	$ 0.08	$ 0.05	$ 0.02	$ 0.00	$ 0.40	$ 0.15	$ (0.27)	$ 0.08	$ 0.06
Diluted	$ 0.17	$ 0.09	$ 0.08	$ 0.05	$ 0.02	$ 0.00	$ 0.39	$ 0.15	$ (0.27)	$ 0.08	$ 0.06