Revenue - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Redemption of loyalty points period			36 months
Revenue, remaining performance obligation	$ 156,500		$ 156,500
Revenues	317,423	$ 295,089	535,463	$ 504,132
Corporate & Other
Disaggregation of Revenue [Line Items]
Revenues	$ 4,100	$ 3,300	$ 7,400	$ 7,000
Minimum
Disaggregation of Revenue [Line Items]
Deferred revenue, recognition period			5 years
Maximum
Disaggregation of Revenue [Line Items]
Deferred revenue, recognition period			10 years