Revenue Recognition Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 162,186	$ 149,362	$ 168,223	$ 149,362	$ 150,144	$ 168,223
Deferred incentive revenue					6,900	7,397
Customer deposits					42,019	39,101
Deferred revenue and customer deposits					$ 199,063	$ 214,721
Change in Contract with Customer, Liability [Abstract]
Beginning balance	162,186	157,986	168,223	140,130
Additions	166,398	190,168	463,652	497,665
Revenue recognized	(178,440)	(198,792)	(481,731)	(488,433)
Ending balance	$ 150,144	$ 149,362	$ 150,144	$ 149,362