Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Principles of Consolidation - Additional Information (Detail)

v3.10.0.1
Basis of Presentation and Principles of Consolidation - Additional Information (Detail)
$ in Millions
9 Months Ended
Sep. 30, 2018
Segment
Dec. 31, 2016
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
New accounting pronouncement or change in accounting principle, effect of adoption, quantification   $ 0.0
Number of reportable segments | Segment 3  
Additional Paid-in Capital [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
New accounting pronouncement or change in accounting principle, effect of adoption, quantification   0.5
Retained Earnings [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
New accounting pronouncement or change in accounting principle, effect of adoption, quantification   $ (0.5)