XML 56 R47.htm IDEA: XBRL DOCUMENT v3.24.2.u1
Common Stock And Preferred Stock - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended 12 Months Ended
Jan. 30, 2024
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Dec. 31, 2023
May 01, 2024
Mar. 31, 2024
Class of Stock [Line Items]                
Common Stock, Shares, Outstanding   16,173,132 16,091,419 16,173,132 16,091,419 16,116,724    
Common stock, shares issued   5,245 5,189 11,048 10,524      
Proceeds from Issuance of Common Stock       $ 600,000 $ 600,000      
Percentage of fully-vested restricted stock units that directors will receive in common shares when settled       70.00%        
Percentage of fully-vested restricted stock units that directors will receive in cash when settled       30.00%        
Preferred Stock   $ 200,000 $ 200,000 $ 200,000 200,000 $ 200,000    
Maximum                
Class of Stock [Line Items]                
Dividend declared       $ 100,000 $ 100,000      
Restricted Stock                
Class of Stock [Line Items]                
Restricted stock vesting period       4 years        
Restricted stock non-vested   59,163 64,243 59,163 64,243      
Restricted Stock Units Granted       $ 47.72 $ 48.02      
Share based compensation expense       $ 1,200,000 $ 1,300,000      
Fair value of liabilities associated with fully vested RSUs that will be settled in cash   $ 800,000 $ 1,000,000 800,000 $ 1,000,000 $ 800,000    
Unrecognized share based compensation   $ 1,100,000   $ 1,100,000        
Share compensation recognition period       2 years 8 months 12 days        
Restricted Stock Units Granted 22,680              
Aggregate Market Value $ 1,100,000              
Forfeitures under the stock plan       0        
Cancellations under the stock plan       0        
Restricted Stock | Maximum                
Class of Stock [Line Items]                
Restricted stock available for awards             1,027,500 677,500
Restricted stock that may be awarded in any one calendar year to any one participant   20,000   20,000        
Restricted Stock | Vesting Annually                
Class of Stock [Line Items]                
Restricted stock vesting percentage annually       25.00%        
Restricted Stock Units (RSUs)                
Class of Stock [Line Items]                
Restricted Stock Units Granted       0        
Restricted stock units outstanding     44,468   44,468      
Weighted-Average Stock Price     $ 40.37   $ 40.37      
Performance Shares                
Class of Stock [Line Items]                
Restricted stock non-vested   43,453 18,770 43,453 18,770      
Restricted Stock Units Granted       $ 50.35 $ 51.83      
Share based compensation expense       $ 500,000 $ 200,000      
Unrecognized share based compensation   $ 1,900,000   $ 1,900,000        
Share compensation recognition period       2 years        
Restricted Stock Units Granted 22,680              
Aggregate Market Value $ 1,100,000              
Forfeitures under the stock plan       0        
Cancellations under the stock plan       0        
Series 6 | Unitil Energy Systems Inc                
Class of Stock [Line Items]                
Preferred stock, outstanding   1,727 1,727 1,727 1,727 1,727    
Preferred Stock   $ 200,000 $ 200,000 $ 200,000 $ 200,000 $ 200,000    
Dividend rate       6.00% 6.00% 6.00%    
Dividend and Distribution Reinvestment and Share Purchase Plan                
Class of Stock [Line Items]                
Proceeds from Issuance of Common Stock       $ 559,300        
Dividend and Distribution Reinvestment and Share Purchase Plan | Average                
Class of Stock [Line Items]                
Common stock price per share   $ 50.62   $ 50.62        
Dividend and Distribution Reinvestment and Share Purchase Plan | Common Stock                
Class of Stock [Line Items]                
Common stock, shares issued       11,048