Equity-Based Compensation - Summary of Activity Relating to Stock Options (Details) - Stock options - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Options
Outstanding at the beginning of the period (in shares)	209,759
Options exercised (in shares)	(72,296)
Outstanding and exercisable at the end of the period (in shares)	137,463	209,759
Weighted- Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 2.98
Options exercised (in dollars per share)	2.92
Outstanding and exercisable at the end of the period (in dollars per share)	$ 3.01	$ 2.98
Weighted- Average Remaining Contractual Term (Years)
Outstanding	3 years 263 days	4 years 6 months