Related Party Transactions - Performance Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Deferred revenue	$ 25,221	$ 20,237	$ 13,280	$ 11,620	$ 11,226	$ 13,544
Lismore Capital LLC and Ashford Trust | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Related Party Transaction [Line Items]
Deferred revenue	$ 9,900
Initial contract period	24 months
Lismore Capital LLC | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Related Party Transaction [Line Items]
Initial contract period	12 months
Braemar | Lismore Capital LLC | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Related Party Transaction [Line Items]
Deferred revenue	$ 2,500
Initial contract period	12 months