Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation and Cash-Based Incentive Compensation - Outstanding Restricted Shares Issued to Non-employee Directors (Details)

v3.10.0.1
Share-Based Compensation and Cash-Based Incentive Compensation - Outstanding Restricted Shares Issued to Non-employee Directors (Details) - Restricted Shares - shares
Jun. 30, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Awards expected to vest by period 181,832 246,528
2019    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Awards expected to vest by period 105,012  
2020    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Awards expected to vest by period 62,972  
2021    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Awards expected to vest by period 13,848