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Stock-Based Compensation - Additional Information (Detail)
3 Months Ended
May 17, 2017
Director
shares
May 18, 2016
Director
shares
Mar. 31, 2018
USD ($)
shares
Mar. 31, 2017
USD ($)
May Two Thousand Sixteen [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Restricted stock expense       $ 100,000
May Two Thousand Seventeen [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Restricted stock expense     $ 100,000  
Restricted Stock [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation awards, requisite service period     3 years  
Restricted Stock [Member] | May Two Thousand Sixteen [Member] | Board of Directors [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Restricted shares of common stock issued | shares   149,448    
Number of non employee directors | Director   3    
Restricted Stock [Member] | May Two Thousand Seventeen [Member] | Board of Directors [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Restricted shares of common stock issued | shares 153,192      
Number of non employee directors | Director 3      
Restricted Stock [Member] | May Two Thousand Seventeen [Member] | Board of Directors [Member] | Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unrecognized compensation cost     $ 100,000  
Restricted Stock Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation awards, requisite service period     3 years  
Unrecognized compensation cost     $ 7,000,000  
Weighted average period for shares to vest     1 year  
Performance Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unrecognized compensation cost     $ 6,400,000  
Weighted average period for shares to vest     2 years  
2014 Long-Term Incentive Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of shares authorized to be issue | shares     25,000,000  
Number of shares are available for future grants | shares     7,199,257