• Filing Date: 2018-03-07
  • Form Type: 10-K
  • Description: Annual report
v3.8.0.1
Subsequent Events - Additional Information (Detail) - USD ($)
12 Months Ended
Feb. 08, 2018
Jan. 26, 2018
Jan. 15, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Feb. 20, 2018
Subsequent Event [Line Items]              
Dividends per common share       $ 1.40 $ 1.20 $ 1.20  
Options to purchase common shares granted       110,000      
Options exercise price per share       $ 40.00      
Grant date fair value of restricted stock       $ 0 $ 0 $ 0  
Capital committed for investment       $ 14,328,000 $ 13,554,000    
Subsequent Event [Member]              
Subsequent Event [Line Items]              
Dividends per common share     $ 0.35        
Date of dividend payable     Mar. 16, 2018        
Record date of dividend payable     Feb. 16, 2018        
Subsequent Event [Member] | Chief Executive Officer [Member]              
Subsequent Event [Line Items]              
Shares of restricted stock granted 40,000            
Options to purchase common shares granted 110,000            
Options exercise price per share $ 40            
Options expiration date Feb. 08, 2028            
Vesting period 4 years            
Grant date fair value of restricted stock $ 1,397,000            
Grant date fair value of stock options $ 939,000            
Subsequent Event [Member] | Greenleaf Essence, LLC [Member]              
Subsequent Event [Line Items]              
Purchase of noncontrolling interest   $ 539,000          
Gain or loss on acquisition of noncontrolling interest   $ 0          
Subsequent Event [Member] | Limited Partnership [Member] | Subscription Agreement [Member]              
Subsequent Event [Line Items]              
Capital committed for investment             $ 5,000,000