Fair Value Measurement - Fair Value of Assets (Liabilities) Not Measured at Fair Value In Consolidated Balance Sheet - Additional Information (Details) - USD ($) $ in Millions |
Sep. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Fixed-Rate Long-Term Debt | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Long term debt, carrying value | $ 120.0 | $ 180.0 |