Quarterly report pursuant to Section 13 or 15(d)

New Accounting Pronouncements (Detail)

v3.7.0.1
New Accounting Pronouncements (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Income tax benefit related to the settlement of share-based awards during period $ 0.1   $ 5.0  
Accounting Standards Update, Statutory Tax Withholding Component        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Net cash provided by (used in) operating activities   $ 1.2   $ 7.2
Net cash provided by (used in) financing activities   (1.2)   (7.2)
Accounting Standards Update, Excess Tax Benefit Component        
New Accounting Pronouncements or Change in Accounting Principle [Line Items]        
Net cash provided by (used in) operating activities   0.1   0.1
Net cash provided by (used in) financing activities   $ (0.1)   $ (0.1)