Revenue Recognition - Summary of Revenue from Prepaid Gift Cards Expected to be Recognized in Future Related to Performance Obligation Unsatisfied or Partially Satisfied (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 11,260
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-10-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 3,765
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 3,556
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 2,026
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 664
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 622
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2024-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, amount	$ 627
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year