Long-Lived Asset Impairment - Narratives (Details) - Corporate Office Relocation - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment
Additions for costs expensed	$ 2,100	$ 0	$ 2,113
Impairment of leasehold improvements and furniture and fixtures
Property, Plant and Equipment
Additions for costs expensed	$ 795		$ 795

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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