Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Stockholders' Equity and Stock Based Compensation - Nonvested (Details)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2018
USD ($)
installment
$ / shares
shares
Mar. 31, 2017
USD ($)
Dec. 31, 2017
installment
$ / shares
shares
General and Administrative Expense      
Weighted Average Grant Date Fair Value      
Share-based compensation cost | $ $ 0.3 $ 0.3  
Restricted stock      
Shares      
Nonvested shares at the beginning of the period 161,818    
Granted (in shares) 60,500   87,076
Vested (in shares) (23,109)    
Forfeited (in shares)     (22,694)
Nonvested shares at the end of the period 199,209   161,818
Weighted Average Grant Date Fair Value      
Nonvested shares at the beginning of period (in dollars per share) | $ / shares $ 15.98    
Granted (in dollars per share) | $ / shares 16.29    
Vested (in dollars per share) | $ / shares 15.14    
Nonvested shares at the end of period (in dollars per share) | $ / shares $ 15.34   $ 15.98
Unrecognized compensation cost (in dollars) | $ $ 3.1    
Weighted average period for recognition of unrecognized compensation cost 2 years 9 months 18 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 16   12