Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Accounts Receivable and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Allowance for Credit Loss, Writeoff	$ 15,300	$ 11,200
Bad debt expense	21,768	22,222	$ 13,291
Corporate and Other
Accounts, Notes, Loans and Financing Receivable
Bad debt expense	$ 1,100	$ 800