Revenue Recognition (Details) - Nature of Services	6 Months Ended
	Jun. 30, 2021
Voice Services [Member]
Revenue Recognition (Details) - Nature of Services [Line Items]
Revenue Recognition Period	1 month
Video Service [Member]
Revenue Recognition (Details) - Nature of Services [Line Items]
Revenue Recognition Period	1 month
Data Service [Member]
Revenue Recognition (Details) - Nature of Services [Line Items]
Revenue Recognition Period	1 month
Product and Service, Other [Member]
Revenue Recognition (Details) - Nature of Services [Line Items]
Revenue Recognition Period	1 month
Minimum [Member] | Other Contracted Revenue [Member]
Revenue Recognition (Details) - Nature of Services [Line Items]
Revenue Recognition Period	3 years
Maximum [Member] | Other Contracted Revenue [Member]
Revenue Recognition (Details) - Nature of Services [Line Items]
Revenue Recognition Period	10 years