Summary Of Significant Accounting Policies Consolidated Statement of Cash Flows - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents		$ 863,279	$ 127,432
Restricted cash	[1]	25,160	26,182
Total cash, cash equivalents, and restricted cash		$ 888,439	$ 153,614	$ 206,916	$ 108,332

[1] (1) Restricted cash balances are included in "prepaid expenses and other assets" on our consolidated balance sheets.