Equity Method Investments Changes in Equity Method Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity			$ 73,925
Investment in equity			1,500
Notes receivable			8,000
Equity in losses of investments	(6,338)	3,777	(5,222)	6,245
Equity interest in investees' other comprehensive income (loss)			(549)
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	77,654		77,654
INOVA Geophysical [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity			73,925
Investment in equity			0
Notes receivable			0
Equity in losses of investments	(4,700)	3,777	(2,876)	6,245
Equity interest in investees' other comprehensive income (loss)			(549)
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	70,500		70,500
GeoRXT [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity			0
Investment in equity			1,500
Notes receivable			8,000
Equity in losses of investments	(1,600)		(2,346)
Equity interest in investees' other comprehensive income (loss)			0
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 7,154		$ 7,154