Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Narrative (Details)

v3.10.0.1
Stock Based Compensation - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of shares authorized (in shares) 4,500,000.0   4,500,000.0  
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Fair value of the award as of the modification dates or grant date $ 9.2   $ 9.2  
Unrecognized compensation cost     22 months  
Compensation expense $ 1.7 $ 1.1 $ 2.9 $ 1.6