Deferred Revenue of Membership Upgrade Sales and Deferred Commission Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Movement in Deferred Revenue
Deferred revenue - upfront payments from membership upgrade sales, beginning of year	$ 218,337
Revenue recognized from membership upgrade sales upfront payments	(16,433)	$ (14,719)	$ (12,958)
Net increase in deferred revenue - upfront payments from membership grade sales	31,148	35,313	33,946
Deferred revenue - upfront payments from membership upgrade sales, beginning of year	229,301	218,337
Movement in Deferred Costs
Deferred commission expense, beginning of year	53,641	50,441
Deferred commission expense	7,452	7,411
Commission expense recognized	(4,577)	(4,211)
Net increase in deferred commission expense	2,875	3,200
Deferred commission expense, end of year	56,516	53,641	50,441
Membership Subscriptions
Movement in Deferred Revenue
Deferred revenue - upfront payments from membership upgrade sales, beginning of year	206,625	185,660
Membership upgrade sales	27,529	35,684
Revenue recognized from membership upgrade sales upfront payments	(16,433)	(14,719)
Net increase in deferred revenue - upfront payments from membership grade sales	11,096	20,965
Deferred revenue - upfront payments from membership upgrade sales, beginning of year	$ 217,721	$ 206,625	$ 185,660