Earnings (Loss) Per Share - Narrative (Details) - shares	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential antidilutive securities excluded from future computations of earnings per share, amount (in shares)	2,012,481	2,251,034	1,969,623	2,243,763

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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