XML 113 R82.htm IDEA: XBRL DOCUMENT v3.10.0.1
Financial Data by Segment and Geographic Area - Schedule of Revenue by Solutions (Detail) - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]          
Total revenue $ 546.1 $ 488.4 $ 670.8 $ 623.4 $ 611.6
HCM [Member]          
Segment Reporting, Revenue Reconciling Item [Line Items]          
Total revenue 546.1 488.4      
HCM [Member] | Cloud Revenue [Member]          
Segment Reporting, Revenue Reconciling Item [Line Items]          
Total revenue 386.0 288.0 404.3 297.8 225.2
HCM [Member] | Bureau Revenue [Member]          
Segment Reporting, Revenue Reconciling Item [Line Items]          
Total revenue $ 160.1 $ 200.4 $ 266.5 $ 325.6 $ 386.4