Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue
Net Revenue	$ 31,791	$ 31,274	$ 32,191	$ 27,816	$ 32,938	$ 31,648	$ 32,234	$ 28,009	$ 123,072	$ 124,829	$ 118,149
Remaining performance obligations on leases one year or less exemption									true
Broadcast Advertising Revenue, Net [Member]
Revenue
Net Revenue									$ 112,278	114,929	109,175
Digital Advertising Revenue [Member]
Revenue
Net Revenue									3,783	3,900	3,610
Other Revenue [Member]
Revenue
Net Revenue									$ 7,011	$ 6,000	$ 5,364