Business Combinations (Schedule of Purchase Price Allocation) (Details) - USD ($)	Dec. 08, 2020	Mar. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill acquired on acquisition		$ 840,632,000	$ 840,610,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted average amortization period	15 years
Software and technology assets [Member]
Business Acquisition [Line Items]
Weighted average amortization period	4 years
Trade Names and Trademarks [Member]
Business Acquisition [Line Items]
Weighted average amortization period	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	7,307,000
Other non-current liabilities	3,188,000
Deferred tax liabilities	936,000
Fair value of identifiable net assets acquired	85,351,000
Goodwill acquired on acquisition	$ 166,373,000
Weighted average amortization period	13 years 9 months 18 days
Rouse Services LLC [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets	$ 71,000,000
Rouse Services LLC [Member] | Software and technology assets [Member]
Business Acquisition [Line Items]
Intangible assets	7,500,000
Rouse Services LLC [Member] | Trade Names and Trademarks [Member]
Business Acquisition [Line Items]
Intangible assets	$ 800,000