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, 2017	Dec. 31, 2016
Fixed-Rate Long-Term Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt, carrying value	$ 265.0	$ 350.0
Variable Interest Entity, Not Primary Beneficiary
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments, present value of estimated future cash flows	120.00%

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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