Deferred Revenue from Membership Upgrade Sales and Deferred Commission Expense (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Movement in Deferred Revenue [Roll Forward]
Deferred revenue - upfront payments from membership upgrade sales, beginning	$ 197,743
Revenue recognized from membership upgrade sales upfront payments	(7,119)	$ (6,236)
Deferred membership revenue	19,618	18,064
Movement in Deferred Sales Inducements [Roll Forward]
Deferred revenue - upfront payments from membership upgrade sales, ending	210,242
Deferred Commissions Expense
Movement in Deferred Sales Inducements [Roll Forward]
Deferred commission expense, beginning	48,806	47,349
Deferred commission expense	3,723	3,527
Commission expense recognized	(2,186)	(2,070)
Net increase in deferred commission expense	1,537	1,457
Deferred commission expense, ending	50,343	48,806
Membership Subscription
Movement in Deferred Revenue [Roll Forward]
Deferred revenue - upfront payments from membership upgrade sales, beginning	174,407	163,957
Membership upgrade sales, gross	17,253	16,686
Revenue recognized from membership upgrade sales upfront payments	(7,119)	(6,236)
Deferred membership revenue	10,134	10,450
Movement in Deferred Sales Inducements [Roll Forward]
Deferred revenue - upfront payments from membership upgrade sales, ending	$ 184,541	$ 174,407