Goodwill and other intangible assets - Additional Information (Details) - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Goodwill and Intangible Assets Disclosure [Abstract] | ||
| Other intangible assets | $ 2,990,000 | $ 2,990,000 |
| Goodwill | 1,243,000 | 1,243,000 |
| Goodwill and intangible asset, impairment | $ 0 | $ 0 |