Additional Cash Flow Information (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 4,831,332	$ 3,109,322	$ 3,294,684	$ 2,650,134
Cash, cash equivalents and restricted cash per statement of cash flows	4,835,700	3,120,681	3,301,646	2,658,253
Prepaid expenses and other current assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents	4,368	8,004	6,962	4,910
Other assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and cash equivalents	$ 0	$ 3,355	$ 0	$ 3,209