Annual report pursuant to Section 13 and 15(d)

Contingencies - Narrative (Details)

v3.8.0.1
Contingencies - Narrative (Details)
6 Months Ended 12 Months Ended
Jul. 29, 2016
defendant
Feb. 09, 2016
defendant
Jul. 29, 2016
claim
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Loss Contingencies [Line Items]            
Number of new claims filed | claim     2      
Insurance proceeds       $ 0 $ (5,718,000) $ (10,015,000)
Uninsured cash amount       97,600,000    
Maximum            
Loss Contingencies [Line Items]            
Cash, FDIC insured amount       $ 250,000    
Judicial District Court for the Parish of Cameron            
Loss Contingencies [Line Items]            
Number of defendants | defendant   26        
Judicial District Court for the Parish of Vermillion            
Loss Contingencies [Line Items]            
Number of defendants | defendant 40