Goodwill and other intangible assets - Additional Information (Details) - USD ($) |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2020 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Goodwill and Intangible Assets Disclosure [Abstract] | ||||
| Depreciation and amortization | $ 1,700,000 | $ 7,000,000 | $ 7,100,000 | $ 7,100,000 |
| Impairment of finite-lived intangible assets | $ 0 | |||