Supplemental Financial Information - Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 1,599,025	$ 1,519,431	$ 1,349,724	$ 928,306
Restricted cash	8,278	2,458	982	1,189
Total cash and cash equivalents, included restricted amounts, beginning of period	$ 1,607,303	$ 1,521,889	$ 1,350,706	$ 929,495