Supplemental Financial Information - Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 1,948,464	$ 1,519,431	$ 1,298,005	$ 928,306
Restricted cash	9,072	2,458	9,121	1,189
Total cash and cash equivalents, included restricted amounts, beginning of period	$ 1,957,536	$ 1,521,889	$ 1,307,126	$ 929,495