Summary of Significant Accounting Policies (General Contractor Revenue) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Costs in Excess of Billings	$ 16,600,000	$ 16,500,000
Billings in Excess of Cost	$ 105,000	$ 159,000

Amount of receivable reflecting the cost incurred on uncompleted contracts in excess of related billings.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(c)(2))
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Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(c)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(c)(4))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Period Type:	instant