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Compensation Plans - Narrative (Detail) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Deferred compensation equity $ (19,440,920)   $ (14,748,118)
Fully vested employee elected deferral period 5 years    
Deferred compensation liability $ 33,369,087   $ 33,241,952
Proceeds received under employee stock purchase plan $ 342,528 $ 0  
2014 Equity and Cash Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common shares available for issuance (in shares) 181,471    
Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock Purchased During Period, Shares, Employee Stock Purchase Plans 2,583    
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent 85.00%    
Proceeds received under employee stock purchase plan $ 300,000    
Share-based payment expense $ 100,000