Contract Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Revenue recognized that was included in the contract liability balance at the beginning of the period	$ (155,255)	$ (76,766)
Contract assets balance	25,454		$ 15,020	$ 14,894
Contract liabilities - current	195,509		184,845	104,901
Contract liabilities - non-current	$ 24,415		$ 13,921	$ 10,921