Financial Instruments - Schedule of Maintenance Fee Payment to CCKF (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
Related Party Transactions [Abstract] | ||||
Maintenance Fee Payments | $ 338 | $ 355 | $ 1,045 | $ 1,108 |