Revenue Recognition - Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Change in Contract with Customer, Liability [Abstract]
Beginning balance	$ 120,643	$ 177,266	$ 135,578	$ 175,455
Additions	195,324	159,244	350,785	297,631
Revenue recognized	(199,712)	(167,257)	(370,108)	(303,833)
Ending balance	$ 116,255	$ 169,253	$ 116,255	$ 169,253