Retirement Benefit Plans - Fair Value of U.S. and Puerto Rico Pension Plan Assets (Detail) - U.S. and Puerto Rico [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	$ 444.9	$ 388.5	$ 433.6
Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	4.7	3.1
Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	440.2	385.4
Cash and Cash Equivalents [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	4.7	3.1
Cash and Cash Equivalents [Member] | Fair Value Measurements at Reporting Date Using: Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	4.7	3.1
Equity Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	282.5	231.7
Equity Securities [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	282.5	231.7
Intermediate Fixed Income Debt Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	157.7	153.7
Intermediate Fixed Income Debt Securities [Member] | Fair Value Measurements at Reporting Date Using: Significant Other Observable Inputs (Level 2) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Plan assets at fair market value	$ 157.7	$ 153.7