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Stock-based Compensation - Additional Information (Detail)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended
Jun. 01, 2014
shares
Feb. 28, 2017
installment
$ / shares
shares
Mar. 31, 2017
USD ($)
shares
Mar. 31, 2016
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Compensation expense associated with grants | $     $ 536 $ 431
Restricted Stock Awards [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Compensation expense associated with grants | $     500 $ 400
Unamortized stock-based compensation expense related to unvested awards | $     $ 5,400  
Weighted-average remaining vesting period     2 years 5 months  
Ensign Employees [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Restricted stock award conversion ratio related to the spin-off 1      
Ensign Employees [Member] | Restricted Stock Awards [Member]        
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)     11,340  
Unvested stock awards outstanding (in shares)     30,840  
Member of Board of Directors [Member] | Restricted Stock Awards [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of restricted stock awards granted (in shares)   233,768    
Restricted stock award grant date fair value (in usd per share) | $ / shares   $ 15.21    
Number of equal annual vesting installments | installment   3