Stockholders' Deficit - Narrative (Details) - Common stock - USD ($)	Sep. 30, 2019	Jan. 31, 2018	Apr. 24, 2017
Class of Stock [Line Items]
Authorized amount for repurchase		$ 300,000,000	$ 150,000,000
Remaining authorized repurchase amount	$ 75,000,000

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.

No definition available.

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