Equity-Based Compensation - Stock Options (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Stock options
Outstanding at the beginning of the period (in shares)	687,929
Options forfeited (in shares)	(10,458)
Outstanding at the end of the period (in shares)	677,471	687,929
Vested or expected to vest (in shares)	677,471
Exercisable (in shares)	364,855
Weighted average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 50.46
Options forfeited (in dollars per share)	50.00
Outstanding at the end of the period (in dollars per share)	50.47	$ 50.46
Vested or expected to vest (in dollars per share)	50.47
Exercisable (in dollars per share)	$ 50.70
Weighted average remaining contractual life
Outstanding	7 years 7 months 10 days	8 years 1 month 13 days
Vested or expected to vest	7 years 7 months 10 days
Exercisable	7 years 6 months 7 days
Additional disclosures
Unrecognized stock-based compensation expense	$ 4.0
Weighted average period for recognizing unrecognized stock-based compensation expense	1 year 9 months 18 days
Minimum
Stock-based compensation
Vesting period	1 year
Maximum
Stock-based compensation
Vesting period	4 years
Contractual life	10 years