Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Total net revenues		$ 55,493	$ 39,261
Radio Advertising
Disaggregation Of Revenue [Line Items]
Total net revenues		$ 30,012	$ 19,129
Radio Advertising | Revenue, Product and Service Benchmark | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of revenue		54.10%	48.70%
Nontraditional
Disaggregation Of Revenue [Line Items]
Total net revenues		$ 4,864	$ 761
Nontraditional | Revenue, Product and Service Benchmark | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of revenue		8.80%	1.90%
Digital
Disaggregation Of Revenue [Line Items]
Total net revenues		$ 2,864	$ 2,256
Digital | Revenue, Product and Service Benchmark | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of revenue		5.20%	5.70%
Outdoor Advertising
Disaggregation Of Revenue [Line Items]
Total net revenues	[1]	$ 12,725	$ 12,459
Outdoor Advertising | Revenue, Product and Service Benchmark | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of revenue	[1]	22.90%	31.70%
Other
Disaggregation Of Revenue [Line Items]
Total net revenues		$ 5,028	$ 4,656
Other | Revenue, Product and Service Benchmark | Product Concentration Risk
Disaggregation Of Revenue [Line Items]
Percentage of revenue		9.00%	12.00%

[1] A substantial portion of this revenue is from lessor revenue derived from operating leases accounted for under ASC 842, “Leases.”