Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity and Stock Based Compensation - Nonvested (Details)

v3.10.0.1
Stockholders' Equity and Stock Based Compensation - Nonvested (Details)
$ / shares in Units, $ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2018
USD ($)
installment
$ / shares
shares
Sep. 30, 2017
USD ($)
Dec. 31, 2017
installment
$ / shares
shares
Selling, general and administrative expenses      
Weighted Average Grant Date Fair Value      
Share-based compensation cost | $ $ 2.6 $ 1.0  
Separation expense | Former Chief Executive Officer      
Weighted Average Grant Date Fair Value      
Share-based compensation cost | $ $ 1.7    
Restricted stock      
Shares      
Nonvested shares at the beginning of the period | shares 161,818    
Granted (in shares) | shares 123,000   87,076
Vested (in shares) | shares (171,679)    
Forfeited (in shares) | shares (7,176)   (22,694)
Nonvested shares at the end of the period | shares 105,963   161,818
Weighted Average Grant Date Fair Value      
Nonvested shares at the beginning of period (in dollars per share) | $ / shares $ 17.26    
Granted (in dollars per share) | $ / shares 14.97    
Vested (in dollars per share) | $ / shares 16.65    
Forfeited (in dollars per share) | $ / shares 15.40    
Nonvested shares at the end of period (in dollars per share) | $ / shares $ 15.70   $ 17.26
Unrecognized compensation cost (in dollars) | $ $ 1.6    
Weighted average period for recognition of unrecognized compensation cost 3 years 2 months 12 days    
Restricted stock | Maximum      
Shares      
Number of equal quarterly installments for vesting of awards | installment 20   20
Restricted stock | Minimum      
Shares      
Number of equal quarterly installments for vesting of awards | installment 1   12