Fair Value Measures - Equity Instruments without Readily Determinable Fair Values (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity investment	$ 50,000	$ 53,700
Quanergy Systems, Inc.
Schedule of Equity Method Investments [Line Items]
Equity investment	50,000	50,000
Lithium Balance A/S
Schedule of Equity Method Investments [Line Items]
Equity investment	$ 0	$ 3,700