Equity-Based Compensation - Summary of Activity Relating to Stock Options (Details) - Stock options - $ / shares	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Options
Outstanding at the beginning of the period (in shares)	79,802
Options exercised (in shares)	(28,624)
Outstanding and exercisable at the end of the period (in shares)	51,178	79,802
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 3.05
Options exercised (in dollars per share)	3.14
Outstanding and exercisable at the end of the period (in dollars per share)	$ 3.00	$ 3.05
Weighted-Average Remaining Contractual Term (Years)
Outstanding	1 year 8 months 12 days	2 years 6 months

Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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