Significant Accounting Policies - Schedule of Balances of Allowance for Doubtful Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 60,465	$ 43,491	$ 39,176
Additions: charges to bad debt expense	44,707	20,324	23,107
Deductions	(28,478)	(3,350)	(18,792)
Balance at end of period	$ 76,694	$ 60,465	$ 43,491