Benefit Plans - Pension Plans with Accumulated Benefit Obligation or Projected Benefit Obligation in Excess of Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
U.S. Pension Plans
Pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	$ 87.2	$ 86.4
Fair value of plan assets	17.5	16.6
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	87.2	86.4
Fair value of plan assets	17.5	16.6
Accumulated benefit obligation	86.3	82.4
Non-US Pension Plans
Pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	165.2	152.7
Fair value of plan assets	20.9	21.4
Pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	165.2	145.0
Fair value of plan assets	20.9	14.2
Accumulated benefit obligation	$ 155.7	$ 136.8