Long-Term Debt (Details) £ in Millions, $ in Millions, $ in Millions			9 Months Ended
	Oct. 01, 2020 USD ($)	Aug. 01, 2020 USD ($)	Sep. 30, 2020 AUD ($) item	Sep. 30, 2020 USD ($)	Sep. 30, 2020 GBP (£)	Aug. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Long Term Debt
Total long-term debt				$ 2,301.7			$ 2,360.3
Less: current portion				(85.6)			(103.3)
Net long-term debt				2,216.1			2,257.0
US Credit Agreement Revolving Credit Line
Long Term Debt
Total long-term debt							45.0
Increase in borrowing capacity		$ 100.0
Maximum credit available		800.0
Revolving loans solely for future U.S. acquisitions		250.0
Future borrowings available for foreign acquisitions		150.0
Maximum amount available for letters of credit		$ 50.0
Incremental interest rate for uncollateralized borrowings in excess of borrowing base (as a percent)		1.25%
Balance outstanding under credit agreement				0.0
US Credit Agreement Revolving Credit Line | LIBOR
Long Term Debt
Base rate of interest on loans		1.75%
UK Credit Agreement Revolving Credit Line
Long Term Debt
Total long-term debt							165.8
Maximum credit available | £					£ 150.0
Additional facility capacity under accordion feature | £					100.0
Balance outstanding under credit agreement				$ 0.0
UK Credit Agreement Revolving Credit Line | Minimum | LIBOR
Long Term Debt
Line of credit basis spread on variable rate (as a percent)			1.10%
UK Credit Agreement Revolving Credit Line | Maximum | LIBOR
Long Term Debt
Line of credit basis spread on variable rate (as a percent)			2.10%
UK Credit Agreement Overdraft Line of Credit
Long Term Debt
Maximum credit available | £					52.0
Amount of demand overdraft lines of credit available during specified time periods each year | £					£ 40.0
Senior Subordinated Notes
Long Term Debt
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)			100.00%	100.00%	100.00%
Change of control, redemption price as a percentage of principal			101.00%
Sale of assets, redemption price as percentage of principal			100.00%
3.75% senior subordinated notes redeemed August 15, 2020
Long Term Debt
Total long-term debt							$ 299.2
Interest rate (as a percent)			3.75%	3.75%	3.75%		3.75%
5.75% senior subordinated notes due 2022
Long Term Debt
Total long-term debt				$ 550.0			$ 547.6
Interest rate (as a percent)	5.75%		5.75%	5.75%	5.75%		5.75%
Principal amount				$ 550.0
Redemption of debt	$ 550.0
5.375% senior subordinated notes due 2024
Long Term Debt
Total long-term debt				$ 298.4			$ 298.0
Interest rate (as a percent)			5.375%	5.375%	5.375%		5.375%
Principal amount				$ 300.0
5.375% senior subordinated notes due 2024 | Debt Instrument Redemption Period On or After December 1, 2019
Long Term Debt
Interest rate (as a percent)			5.375%	5.375%	5.375%
3.50% senior subordinated notes due 2025
Long Term Debt
Total long-term debt				$ 542.9
Interest rate (as a percent)			3.50%	3.50%	3.50%	3.50%
Principal amount				$ 550.0		$ 550.0
3.50% senior subordinated notes due 2025 | Debt Instrument Redemption Period Prior To September 2022
Long Term Debt
Interest rate (as a percent)			3.50%	3.50%	3.50%
Percentage of principal amount at which the entity may redeem the notes			100.00%
Specified equity offerings, percentage of debt which may be redeemed			103.50%
3.50% senior subordinated notes due 2025 | Minimum | Debt Instrument Redemption Period Prior To September 2022
Long Term Debt
Percentage of principal amount at which the entity may redeem the notes			40.00%
5.50% senior subordinated notes due 2026
Long Term Debt
Total long-term debt				$ 496.2			$ 495.7
Interest rate (as a percent)			5.50%	5.50%	5.50%		5.50%
Principal amount				$ 500.0
5.50% senior subordinated notes due 2026 | Debt Redemption Prior to May 15, 2021
Long Term Debt
Interest rate (as a percent)			5.50%	5.50%	5.50%
Percentage of principal amount at which the entity may redeem the notes			100.00%
5.50% senior subordinated notes due 2026 | Debt Instrument Redemption Period On or After May 15, 2021
Long Term Debt
Interest rate (as a percent)			5.50%	5.50%	5.50%
Australia capital loan agreement
Long Term Debt
Total long-term debt				$ 30.7			$ 31.7
Maximum credit available			$ 50.0
Debt term			5 years
Call period			90 days
Maximum amount of debt guaranteed by the Company's U.S. parent company			$ 50.0
Balance outstanding under credit agreement			$ 42.9	30.7
Number of facilities | item			2
Australia capital loan agreement | Australian BBSW 30-Day Bill Rate
Long Term Debt
Base rate of interest on loans			30-day Bill Rate
Line of credit basis spread on variable rate (as a percent)			3.00%
Australia working capital loan agreement
Long Term Debt
Maximum credit available			$ 50.0
Debt term			1 year
Call period			90 days
Maximum amount of debt guaranteed by the Company's U.S. parent company			$ 50.0
Balance outstanding under credit agreement				0.0
Australia working capital loan agreement | Australian BBSW 30-Day Bill Rate
Long Term Debt
Base rate of interest on loans			30-day Bill Rate
Line of credit basis spread on variable rate (as a percent)			3.00%
Mortgage facilities
Long Term Debt
Total long-term debt				333.8			423.2
Balance outstanding under credit agreement				333.8
Other debt
Long Term Debt
Total long-term debt				$ 49.7			$ 54.1