Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 427,142	$ 750,147	$ 284,008
Restricted cash	106,770	117,151	33,122
Total Cash and cash equivalents and Restricted cash shown in the Consolidated Statements of Cash Flows	$ 533,912	$ 867,298	$ 317,130