Summary of Significant Accounting Policies - Reconciliation of cash, cash equivalents and restricted cash (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 1,515,116	$ 553,398
Restricted cash current	11,490	93,880
Restricted cash, noncurrent	1,653	1,460
Cash, cash equivalents and restricted cash	$ 1,528,259	$ 648,738	$ 82,180	$ 81,959