Supplemental Financial Information - Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 555,550	$ 1,519,431	$ 1,547,162	$ 928,306
Restricted cash	8,695	2,458	16,336	1,189
Total cash and cash equivalents, included restricted amounts, beginning of period	$ 564,245	$ 1,521,889	$ 1,563,498	$ 929,495