Summary of Significant Accounting Policies - Accounts Receivable and Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Allowance for doubtful accounts receivable	$ 20,600	$ 15,100	$ 21,000
Allowance for doubt increase	5,500
Accounts Receivable Agreement 1
Property, Plant and Equipment [Line Items]
Maximum amount available to be sold under agreement	140,000
Accounts Receivable Agreement 2
Property, Plant and Equipment [Line Items]
Maximum amount available to be sold under agreement	$ 50,000