Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v3.8.0.1
Income Taxes - Additional Information (Detail)
9 Months Ended
Sep. 30, 2017
USD ($)
Income Tax Contingency [Line Items]  
Deferred tax assets, valuation allowance $ 0
Internal Revenue Service [Member] | Earliest Tax Year [Member]  
Income Tax Contingency [Line Items]  
Open tax year 2011
Internal Revenue Service [Member] | Latest Tax Year [Member]  
Income Tax Contingency [Line Items]  
Open tax year 2014