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Share-Based Compensation - Additional Information (Details)
12 Months Ended
Dec. 31, 2018
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Long-term equity incentive plan, termination date May 01, 2023
Number of shares authorized under plan 10,600,000
Number of shares available for future issuance under share-based plan 700,000
Restricted Stock | Officers and Employees  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 4 years
Performance Units  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period of ROIC as performance measure 4 years
Vesting period of TSR as performance measure 3 years
Percentage of ROIC as performance measure 50.00%
Percentage of TSR as performance measure 50.00%