Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation and Cash-Based Incentive Compensation - Additional Information (Details)

v3.10.0.1
Share-Based Compensation and Cash-Based Incentive Compensation - Additional Information (Details) - USD ($)
 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]        
Common stock available for award under plans 13,342,827   13,342,827  
Recognized incentive compensation expense $ 1,215,000 $ 2,412,000 $ 2,434,000 $ 4,340,000
Restricted Stock Units (RSUs)        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares granted     0  
Unrecognized share-based compensation expense 3,900,000   $ 3,900,000  
Recognition period for unrecognized compensation expense     2019-11  
Recognized incentive compensation expense 1,145,000 2,342,000 $ 2,294,000 4,200,000
Restricted Shares        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares granted     41,544  
Unrecognized share-based compensation expense 500,000   $ 500,000  
Recognition period for unrecognized compensation expense     2021-04  
Recognized incentive compensation expense $ 70,000 $ 70,000 $ 140,000 $ 140,000
2017 Cash-based Awards        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Cash based award expected payment period     2018-03  
2017 Cash-based Awards | Minimum        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Adjusted EBITDA less interest expense     $ 200,000,000  
2016 Cash-based Awards        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Recognized incentive compensation expense     $ 0  
Cash based compensation payment period after achievement of financial condition     30 days  
2016 Cash-based Awards | Minimum        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Adjusted EBITDA less interest expense     $ 300,000,000  
Amended and Restated Incentive Compensation Plan        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Amendment increased the number of shares available in the Plan     7,700,000  
Directors Compensation Plan        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Common stock available for award under plans 128,980   128,980