Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Details)

v3.8.0.1
Income Taxes - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 07, 2018
Dec. 31, 2017
Income Tax Expense (Benefit), Continuing Operations [Abstract]        
Income tax expense (benefit) $ 109,000 $ (7,588,000)    
Income tax expense (benefit) excluding interest on uncertain positions 0 0    
Current tax expense 0 0    
Income tax refund received 0 0    
Cash paid for income taxes 0 $ 0    
Current income taxes receivable 65,103,000   $ 13,000,000 $ 13,006,000
Non-current income taxes receivable     $ 52,100,000 52,097,000
Valuation allowance $ 165,700,000     $ 171,500,000
Minimum        
Income Tax Expense (Benefit), Continuing Operations [Abstract]        
Tax years under examination 2013      
Maximum        
Income Tax Expense (Benefit), Continuing Operations [Abstract]        
Tax years under examination 2017