Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Net income	$ 20,558	$ 3,302
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization (other than multi-client library)	6,825	7,476
Amortization of multi-client library	38,918	36,748
Stock-based compensation expense	2,992	3,134
Equity in (earnings) losses of INOVA Geophysical	(6,245)	5,033
Deferred income taxes	(2,225)	(8,192)
Change in operating assets and liabilities:
Accounts receivable	61,701	11,422
Unbilled receivables	(32,300)	25,284
Inventories	(5,447)	(22,051)
Accounts payable, accrued expenses and accrued royalties	9,041	(15,847)
Deferred revenue	(6,176)	16,630
Other assets and liabilities	(1,912)	(2,127)
Net cash provided by operating activities	85,730	60,812
Cash flows from investing activities:
Investment in multi-client data library	(52,581)	(46,102)
Purchase of property, plant and equipment	(4,890)	(7,240)
Investment in seismic rental equipment	(1,384)
Maturity (net purchases) of short-term investments	20,000	(39,000)
Investment in convertible notes	(1,000)	(6,500)
Other investing activities		50
Net cash used in investing activities	(39,855)	(98,792)
Cash flows from financing activities:
Payments on long-term debt	(2,081)	(3,388)
Repayment of term loan	(98,250)
Borrowings under amended revolving line of credit	98,250
Payments under amended revolving line of credit	(1,000)
Cost associated with debt amendment	(1,313)
Payment of preferred dividends	(676)	(676)
Proceeds from exercise of stock options	317	12,931
Other financing activities	(101)	267
Net cash (used in) provided by financing activities	(4,854)	9,134
Effect of change in foreign currency exchange rates on cash and cash equivalents	(141)	380
Net increase (decrease) in cash and cash equivalents	40,880	(28,466)
Cash and cash equivalents at beginning of period	42,402	84,419
Cash and cash equivalents at end of period	83,282	55,953
Non-cash items from investing and financing activities:
Purchase of computer equipment financed through capital leases	2,953
Transfer of inventory to seismic rental equipment	6,053	2,978
Reduction in multi-client data library related to finalization of accrued liabilities		$ 1,888