Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 629,551	$ 339,629	$ 209,831
Restricted cash	185,702	186,921	185,494
Total Cash and cash equivalents and Restricted cash shown in the Consolidated Statements of Cash Flows	$ 815,253	$ 526,550	$ 395,325	$ 583,572