Accounts Receivable (Narrative) (Details)	6 Months Ended
Jun. 30, 2020
Receivables [Abstract]
Construction receivables, to be collected after year one, interest rate	2.00%
Noncurrent receivables invoice terms	over a 10-year

Rate of interest on amount billed to customer under long-term contract or program to be collected after next fiscal year following current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=119991564&loc=SL119991595-234733

Name:	us-gaap_ConstructionContractorReceivableToBeCollectedAfterYearOneInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant