Equity-Based Compensation - Stock Options (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Stock options
Outstanding at the beginning of the period (in shares)	720,887
Options forfeited (in shares)	(31,625)
Outstanding at the end of the period (in shares)	689,262	720,887
Vested or expected to vest (in shares)	689,262
Exercisable (in shares)	203,590
Weighted average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 50.44
Options forfeited (in dollars per share)	50.00
Outstanding at the end of the period (in dollars per share)	50.46	$ 50.44
Vested or expected to vest (in dollars per share)	50.46
Exercisable (in dollars per share)	$ 50.95
Weighted average remaining contractual life
Outstanding	8 years 4 months 13 days	9 years 1 month 21 days
Vested or expected to vest	8 years 4 months 13 days
Exercisable	8 years 2 months 9 days
Additional disclosures
Unrecognized stock-based compensation expense	$ 6.0
Weighted average period for recognizing unrecognized stock-based compensation expense	2 years 6 months
Minimum
Stock-based compensation
Vesting period	1 year
Maximum
Stock-based compensation
Vesting period	4 years
Contractual life	10 years