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Property and Equipement (Details) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Property, Plant and Equipment    
Gross $ 324,950,000 $ 345,619,000
Less accumulated depreciation (214,033,000) (198,052,000)
Net property and equipment 110,917,000 147,567,000
Land, building and other    
Property, Plant and Equipment    
Gross $ 15,777,000 16,357,000
Land, building and other | Minimum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 3 years  
Land, building and other | Maximum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 40 years  
Recording equipment    
Property, Plant and Equipment    
Gross $ 199,068,000 212,541,000
Recording equipment | Minimum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 5 years  
Recording equipment | Maximum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 10 years  
Line clearing equipment    
Property, Plant and Equipment    
Gross $ 1,071,000 1,071,000
Estimated useful lives of property and equipment 5 years  
Vibrator energy sources    
Property, Plant and Equipment    
Gross $ 79,162,000 80,454,000
Vibrator energy sources | Minimum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 5 years  
Vibrator energy sources | Maximum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 15 years  
Vehicles    
Property, Plant and Equipment    
Gross $ 29,872,000 $ 35,196,000
Vehicles | Minimum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 1 year 6 months  
Vehicles | Maximum    
Property, Plant and Equipment    
Estimated useful lives of property and equipment 10 years