Leases - Additional Details Related to Leases Recorded on the Balance Sheet (Details) - USD ($) $ in Millions |
Jun. 30, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|---|
| Business Acquisition [Line Items] | |||
| Operating lease right-of-use assets, net | $ 35.0 | $ 36.8 | |
| Current portion of operating lease liabilities | 4.0 | 4.0 | |
| Operating lease liabilities, net of current portion | $ 38.3 | 40.7 | |
| DiscoverOrg Holdings | |||
| Business Acquisition [Line Items] | |||
| Operating lease right-of-use assets, net | 36.8 | $ 0.0 | |
| Current portion of operating lease liabilities | 4.0 | 0.0 | |
| Operating lease liabilities, net of current portion | $ 40.7 | $ 0.0 |