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Stock-Based Compensation - Narrative (Details)
$ / shares in Units, $ in Millions
1 Months Ended 6 Months Ended
Jun. 01, 2014
shares
May 31, 2018
$ / shares
shares
Feb. 28, 2018
installment
$ / shares
shares
Jun. 30, 2018
USD ($)
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unamortized stock-based compensation expense related to unvested awards | $       $ 6.4
Weighted average remaining vesting period related to expense recognition       2 years 4 months 24 days
Ensign Employees        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Restricted stock award conversion ratio related to the spin-off 1      
Restricted Stock Award | Ensign Employees        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock awards unvested during spin-off (in shares) 207,580      
Shares vested (in shares)       9,700
Unvested stock awards outstanding (in shares)       5,280
Restricted Stock Award | Officer        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of awards granted (in shares)     141,060  
Award grant date fair value (in usd per share) | $ / shares     $ 15.13  
Number of equal annual vesting installments | installment     4  
Restricted Stock Award | Director        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of awards granted (in shares)   26,462    
Award grant date fair value (in usd per share) | $ / shares   $ 16.44    
Performance Stock Award | Officer        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of awards granted (in shares)     120,460  
Award grant date fair value (in usd per share) | $ / shares     $ 15.13