Related Party Transactions (Executive Officers) (Narrative) (Details)	12 Months Ended
Dec. 31, 2020 USD ($) numberOfEmployees	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Management [Member] \| Subcontracting Arrangements [Member]
Related Party Transaction [Line Items]
Number of management members, subcontracting arrangement \| numberOfEmployees	2
Payments or expenses, related party	$ 1,900,000	$ 10,300,000	$ 9,900,000
Payables, related party	1,400,000	200,000
Executive Officers [Member] \| Related Customer [Member]
Related Party Transaction [Line Items]
Receivables, related party	900,000	800,000
Charges, related party	1,300,000	1,400,000	1,700,000
Executive Officers [Member] \| Construction Services [Member]
Related Party Transaction [Line Items]
Payments or expenses, related party	300,000
Payables, related party	0
Revenue, related party	7,100,000	12,600,000
Receivables, related party		3,900,000
Chairman, Board of Directors [Member] \| Leases [Member]
Related Party Transaction [Line Items]
Payments or expenses, related party	$ 2,600,000	$ 2,400,000	$ 2,700,000

Number of persons from management with an ownership interest in the related party entity.

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Amount for accounts payable to related parties.

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For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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