Stock-Based Compensation - Stock Options and Grants (Details) - shares	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options or grants (in shares)	0	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.

No definition available.

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Period Type:	duration