Revenue Recognition (Narrative) (Details) - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
REVENUE RECOGNITION
Gain (Loss) on Sale of Assets and Asset Impairment Charges	$ 0	$ 0
Minimum [Member] \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
REVENUE RECOGNITION
Period over which unsatisfied performance obligations are expected to be recognized	1 year
Maximum [Member] \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
REVENUE RECOGNITION
Period over which unsatisfied performance obligations are expected to be recognized	3 years

Amount of impairment loss for asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

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+ References

No definition available.

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- Definition

Period in which remaining performance obligation is expected to be recognized as revenue, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

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