Consolidated Financial Statements' Components - Depreciation, Amortization and Accretion (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total depreciation	$ 3,840,000	$ 2,891,000	$ 4,056,000
Amortization
Intangible assets	0	0	417,000
Capitalized software development costs	0	0	5,357,000
Total amortization	0	0	5,774,000
Accretion	656,000	680,000	616,000
Total depreciation, amortization and accretion expense	4,496,000	3,571,000	10,446,000
Leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciation	87,000	64,000	88,000
Asset retirement costs
Property, Plant and Equipment [Line Items]
Asset retirement costs	(261,000)	(702,000)	(87,000)
Paging and computer equipment
Property, Plant and Equipment [Line Items]
Depreciation	3,792,000	3,289,000	3,797,000
Furniture, fixtures and vehicles
Property, Plant and Equipment [Line Items]
Depreciation	$ 222,000	$ 240,000	$ 258,000