XML 70 R48.htm IDEA: XBRL DOCUMENT v3.6.0.2
Accounts receivable - Additional Information (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Receivables [Abstract]      
Revenue recognized in excess of billings on services contracts or unbilled accounts receivable $ 98.0 $ 93.5  
Leases Receivable, 2017 27.9    
Leases Receivable, 2018 30.0    
Leases Receivable, 2019 20.3    
Leases Receivable, 2020 8.1    
Leases Receivable, 2021 0.6    
Leases Receivable, thereafter 0.2    
Unearned income deducted from accounts and notes receivable 7.0 10.9  
Allowance for doubtful accounts 22.8 21.1  
Provision expense for doubtful accounts reported in selling, general and administrative expenses $ 2.2 $ 3.0 $ 2.7