Equity Method Investments Narrative (Details) (USD $)	3 Months Ended		6 Months Ended				3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Apr. 25, 2013	Dec. 31, 2012	Jun. 30, 2013 GeoRXT [Member]	Jun. 30, 2013 GeoRXT [Member]	Feb. 19, 2013 GeoRXT [Member]	Jun. 30, 2013 INOVA Geophysical [Member]	Jun. 30, 2012 INOVA Geophysical [Member]	Jun. 30, 2013 INOVA Geophysical [Member]	Jun. 30, 2012 INOVA Geophysical [Member]	Jun. 30, 2013 Optional Increase in Ownership [Member] GeoRXT [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of equity method investment					16.00%				30.00%	49.00%		49.00%		50.00%
Optional capital contribution to GeoRXT to increase ownership percentagel			$ 9,500,000	$ 0										$ 40,000,000
Amount of purchased interest in joint venture entity									1,500,000
Amount of short-term working capital loan to related party									8,000,000
Equity in losses of investments	(6,338,000)	3,777,000	(5,222,000)	6,245,000			(1,600,000)	(2,346,000)		(4,700,000)	3,777,000	(2,876,000)	6,245,000
Equity method investments	77,654,000		77,654,000			73,925,000	0	0
Equity method investments, notes receivable reduction							$ (800,000)