Fair Value Measurement - Fair Value of Assets (Liabilities) Not Measured at Fair Value In Consolidated Balance Sheet - Additional Information (Details) - USD ($) |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Dec. 31, 2017 |
|
| Fixed-Rate Long-Term Debt | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Long term debt, carrying value | $ 265,000,000 | $ 265,000,000 |
| Variable Interest Entity, Not Primary Beneficiary | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Asset impairment charges | $ 0 |