Fair Value Measurement - Narrative (Details) - USD ($) $ in Millions	Dec. 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	$ 180.0	$ 265.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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