Borrowings - SBI Bonds (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 JPY (¥)	Dec. 31, 2022 JPY (¥)	Jul. 25, 2016 USD ($)	Jul. 25, 2016 JPY (¥)
Debt Instrument [Line Items]
Outstanding principal amount	$ 1,751,816,000	$ 1,826,693,000
SBI bonds
Debt Instrument [Line Items]
Outstanding principal amount	24,816,000	26,693,000
VFH | SBI bonds | SBI Bonds
Debt Instrument [Line Items]
Face amount						$ 33,100,000	¥ 3,500,000,000
Outstanding principal amount	24,800,000	26,700,000		¥ 3,500,000,000	¥ 3,500,000,000
Gain (loss) on due to change in currency rates	$ 1,900,000	$ 4,000,000	$ 3,200,000