Revenue Recognition - Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 170,034	$ 140,734	$ 170,034	$ 168,223
Deferred incentive revenue			7,232	7,397
Customer deposits			42,707	39,101
Deferred revenue and customer deposits			$ 219,973	$ 214,721
Change in Contract with Customer, Liability [Roll Forward]
Beginning balance	168,223	140,130
Additions	138,113	118,359
Revenue recognized	(136,302)	(117,755)
Ending balance	$ 170,034	$ 140,734