Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Trade, allowance for doubtful accounts	$ 175	$ 176
Seismic data library, accumulated amortization	1,276,498	1,274,808
Property and equipment, accumulated depreciation and amortization	17,140	17,346
Intangible assets, accumulated amortization	$ 48,663	$ 49,485
Common stock, par value per share (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	100	100
Common stock, issued (in shares)	100	100
Common stock, outstanding (in shares)	100	100