Borrowings - Interest Expense Related to Convertible and Exchangeable Notes (Details) - Convertible notes and exchangeable notes - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Debt Instrument [Line Items]
Interest expense—stated coupon rate	$ 3,972	$ 5,799	$ 8,895	$ 11,598
Interest expense—amortization of debt discount	0	3,095	0	6,139
Total interest expense	$ 3,972	$ 8,894	$ 8,895	$ 17,737

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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