Related Party Transactions - Indebtedness And Other Obligations Payment Guarantees (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Related Party Transaction [Line Items]
Amount Guaranteed	$ 7,698
Payment Guarantee to Industrial Bank of Korea
Related Party Transaction [Line Items]
Amount Guaranteed	6,077
Payment Guarantee to Shinhan Bank
Related Party Transaction [Line Items]
Amount Guaranteed	$ 1,621