Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation and Other Benefit Plans - Summary of Share-Based Compensation Expense (Details)

v3.19.2
Share-Based Compensation and Other Benefit Plans - Summary of Share-Based Compensation Expense (Details)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jan. 31, 2017
tranche
Jun. 30, 2019
USD ($)
shares
Jun. 30, 2018
USD ($)
shares
Jun. 30, 2019
USD ($)
$ / shares
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Dividends | $       $ 0 $ 0  
Share-based compensation (equity-classified) | $   $ 1,000 $ 900 2,055 2,451  
Share-based Payment Arrangement, Accelerated Cost | $         600  
Separation Agreement, Consulting Fees | $           $ 300
Defined Contribution Plan, Cost | $   100 200 300 300  
Other Pension, Postretirement and Supplemental Plans [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Pension and Other Postretirement Benefits Cost (Reversal of Cost) | $   $ 0 $ 0 $ 0 $ 0  
Time Vested Restricted Stock Units [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   348,572   348,572    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares       $ 43.06 $ 43.43  
Shares, Issued | shares   26,671 38,115 26,671 38,115  
Time Vested Restricted Stock Units [Member] | Minimum [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period       4 years    
Time Vested Restricted Stock Units [Member] | Maximum [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period       5 years    
Performance Restricted Stock Units [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   0 98,526 0 98,526  
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period       5 years    
Shares, Issued | shares   1,495 1,495 1,495 1,495  
Share-based Compensation Arrangements By Share-based Payment Award, Performance Period 3 years          
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum       1.44%    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum       1.51%    
Performance Restricted Stock Units [Member] | Minimum [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate       59.63%    
Share-based Compensation Arrangements By Share-based Payment Award, Number Of Award Tranches | tranche 2          
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage       0.00%    
Performance Restricted Stock Units [Member] | Maximum [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate       62.18%    
Share-based Compensation Arrangements By Share-based Payment Award, Number Of Award Tranches | tranche 3          
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage       200.00%    
Performance Restricted Stock Units [Member] | Year 1 [Member] | Minimum [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares       $ 47.70    
Performance Restricted Stock Units [Member] | Year 2 [Member] | Maximum [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares       $ 65.28    
Time Vested Restricted Stock Units - Employees [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   1,132 17,456 1,132 17,456  
Employees and Directors [Member]            
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   1,424,600   1,424,600