Long-Term Debt (Details) £ in Millions, $ in Millions, $ in Millions		12 Months Ended
	Jan. 01, 2020	Dec. 31, 2019 USD ($) item	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 AUD ($)	Jul. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017
Long Term Debt
Total long-term debt		$ 2,360.3				$ 2,216.7
Less: current portion		(103.3)				(92.0)
Net long-term debt		2,257.0				2,124.7
Scheduled maturities of long-term debt for each of the next five years and thereafter
2020		103.3
2021		16.3
2022		997.4
2023		185.1
2024		322.4
2024 and thereafter		735.8
US Credit Agreement Revolving Credit Line
Long Term Debt
Total long-term debt		45.0				30.0
Maximum credit available		700.0			$ 700.0
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		45.0
US Credit Agreement Revolving Credit Line | LIBOR
Long Term Debt
Line of credit basis spread on variable rate (as a percent)	1.75%
UK Credit Agreement Revolving Credit Line
Long Term Debt
Total long-term debt		$ 165.8				163.3
Maximum credit available | £			£ 150.0
Additional facility capacity under accordion feature | £			100.0
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
Total long-term debt						1.8
UK Credit Agreement Revolving Credit Line and Overdraft Line Of Credit
Long Term Debt
Balance outstanding under credit agreement		$ 165.8	£ 125.0
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%
5.50% senior subordinated notes due 2026
Long Term Debt
Total long-term debt		$ 495.7				$ 495.1
Interest rate (as a percent)		5.50%	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%
5.375% senior subordinated notes due 2024
Long Term Debt
Total long-term debt		$ 298.0				$ 297.6
Interest rate (as a percent)		5.375%	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%
5.75% senior subordinated notes due 2022
Long Term Debt
Total long-term debt		$ 547.6				$ 546.8
Interest rate (as a percent)		5.75%	5.75%	5.75%		5.75%	5.75%
Principal amount		$ 550.0
3.75% senior subordinated notes due 2020
Long Term Debt
Total long-term debt		$ 299.2				$ 297.9
Interest rate (as a percent)		3.75%	3.75%	3.75%		3.75%	3.75%
Principal amount		$ 300.0
Percentage of principal amount at which the entity may redeem the notes		100.00%
Australia capital loan agreement
Long Term Debt
Total long-term debt		$ 31.7				$ 33.6
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		$ 31.7		45.2
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
Total long-term debt						6.1
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		$ 423.2				289.6
Balance outstanding under credit agreement		423.2
Other debt
Long Term Debt
Total long-term debt		$ 54.1				$ 54.9