Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Detail)

v3.8.0.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Contingency [Line Items]      
Change in valuation allowance (excluding impact of Tax Act) $ 30,704 $ 117,707 $ 40,676
Liability for unrecognized tax benefits 5,395 4,628  
Accrued interest and penalties related to uncertain tax positions 2,100 1,900  
Unrecognized tax benefits, interest on tax expense 200    
Unrecognized tax benefits, tax penalties 0    
Deferred tax valuation allowance      
Income Tax Contingency [Line Items]      
Charged to cost and expenses $ (14,625) $ 117,707 $ 40,676