Financial Instruments - Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cash and cash equivalents	[1]	$ 396,035	$ 246,947
Restricted cash		219,079	169,763
Cash, cash equivalents and restricted cash		615,114	416,710	$ 377,388	$ 280,485
Cash
Debt Securities, Available-for-sale [Line Items]
Cash, cash equivalents and restricted cash		318,080	180,808
Money market funds
Debt Securities, Available-for-sale [Line Items]
Cash, cash equivalents and restricted cash		$ 297,034	$ 235,902

[1] We have variable interest entities, which represent a portion of the consolidated balances recorded within these financial statement line items in the consolidated balance sheets (see Note 11 - Portfolio Financings).