Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 561,330	$ 750,147	$ 299,686
Restricted cash	106,633	117,151	40,922
Total Cash and cash equivalents and Restricted cash shown in the Consolidated Statements of Cash Flows	$ 667,963	$ 867,298	$ 340,608