Income Taxes (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of the expected income tax expense on income (loss) before income taxes using the statutory federal income tax
Expected income tax expense at 35%									$ (21,107)	$ (7,389)	$ (37,428)
Foreign tax rate differential									5,932	1,769	(10,481)
Foreign tax differences									(4,828)	4,104	6,444
State and local taxes									28	41	(42)
Nondeductible expenses									(259)	578	(1,584)
Goodwill impairment									0	0	9,444
Expired Capital Loss									1,321	15,950	0
Valuation allowance:
Valuation allowance on equity in losses of INOVA Geophysical									0	0	17,644
Valuation allowance on expiring capital losses									(1,321)	(15,950)	0
Valuation allowance on operations									24,655	4,941	36,585
Income tax expense	$ (1,444)	$ 3,316	$ 2,256	$ 293	$ 447	$ 2,082	$ 532	$ 983	$ 4,421	$ 4,044	$ 20,582