Business Combinations (Schedule of Purchase Price Allocation) (Details) - USD ($)	Dec. 08, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Intangible assets	$ 79,300,000
Goodwill acquired on acquisition		$ 840,610,000	$ 672,310,000	$ 671,594,000
Amortization life	13 years 9 months 18 days
Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets	$ 71,000,000
Amortization life	15 years
Computer Software, Intangible Asset [Member]
Business Acquisition [Line Items]
Intangible assets	$ 7,500,000
Amortization life	4 years
Trade Names and Trademarks [Member]
Business Acquisition [Line Items]
Intangible assets	$ 800,000
Amortization life	2 years
Rouse Services LLC [Member]
Business Acquisition [Line Items]
Purchase price	$ 251,724,000
Cash and cash equivalents	226,000
Trade and other receivables	4,601,000
Other current assets	159,000
Property, plant and equipment	1,171,000
Other non-current assets	3,741,000
Deferred tax assets	7,584,000
Intangible assets	79,300,000
Trade and other payables	6,704,000
Other non-current liabilities	3,188,000
Deferred tax liabilities	936,000
Fair value of identifiable net assets acquired	85,954,000
Goodwill acquired on acquisition	$ 165,770,000