Fair Value of Financial Instruments (Other Investments - Telecommunications Entities) (Narrative) (Details) - Equity Investee [Member] - Subcontracting Arrangements [Member] $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($) entity
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Number of entities \| entity		3
Payments or expenses, related party	$ 3.6	$ 6.3
Payables, related party	$ 0.4	$ 0.4

Amount for accounts payable to related parties.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 10
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant