Goodwill and Intangible Assets - Goodwill and Intangible Assets Subject to Amortization (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 11,212	$ 11,171
Accumulated Amortization	9,750	8,917
Net Carrying Value	1,462	2,254
Subscriber relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,014	7,977
Accumulated Amortization	6,552	5,958
Net Carrying Value	1,462	2,019
Distribution rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	315	311
Accumulated Amortization	315	76
Net Carrying Value	0	235
Internally developed software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	446	446
Accumulated Amortization	446	446
Net Carrying Value	0	0
Proprietary content
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	153	153
Accumulated Amortization	153	153
Net Carrying Value	0	0
Intellectual property
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,284	2,284
Accumulated Amortization	2,284	2,284
Net Carrying Value	$ 0	$ 0