Quarterly report pursuant to Section 13 or 15(d)

Equity-Based Compensation - Stock Options (Details)

v3.19.1
Equity-Based Compensation - Stock Options (Details) - Stock options - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Stock options    
Outstanding at the beginning of the period (in shares) 579,617  
Options forfeited (in shares) (33,312)  
Outstanding at the end of the period (in shares) 546,305 579,617
Vested or expected to vest (in shares) 546,305  
Exercisable (in shares) 433,155  
Weighted average exercise price    
Outstanding at the beginning of the period (in dollars per share) $ 50.55  
Options forfeited (in dollars per share) 50.00  
Outstanding at the end of the period (in dollars per share) 50.58 $ 50.55
Vested or expected to vest (in dollars per share) 50.58  
Exercisable (in dollars per share) $ 50.73  
Weighted average remaining contractual life    
Outstanding 5 years 8 months 12 days 5 years 9 months 22 days
Vested or expected to vest 5 years 8 months 12 days  
Exercisable 5 years 7 months 10 days  
Additional disclosures    
Unrecognized stock-based compensation expense $ 0.1  
Maximum    
Stock-based compensation    
Contractual life 10 years  
Additional disclosures    
Weighted average period for recognizing unrecognized stock-based compensation expense 1 year