XML 22 R48.htm IDEA: XBRL DOCUMENT v2.4.0.8
Equity - Additional Information (Detail) (USD $)
 12 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Apr. 21, 2011
Apr. 21, 2011
Before Amendment
Dec. 31, 2013
Non Vested Restricted Stock
Dec. 31, 2012
Non Vested Restricted Stock
Dec. 31, 2011
Non Vested Restricted Stock
Dec. 31, 2013
Restricted Stock Units
Dec. 31, 2012
Restricted Stock Units
Maximum
Dec. 31, 2013
Restricted Stock
Y
Dec. 31, 2012
Restricted Stock
Dec. 31, 2011
Restricted Stock
Dec. 31, 2013
Restricted Stock
Maximum
Dec. 31, 2013
Restricted Stock Units
May 16, 2012
Common Stock Offering
Dec. 31, 2013
Dividend and Distribution Reinvestment and Share Purchase Plan
Dec. 31, 2012
Dividend and Distribution Reinvestment and Share Purchase Plan
Dec. 31, 2011
Dividend and Distribution Reinvestment and Share Purchase Plan
Dec. 31, 2013
Unitil Energy Systems Inc
Series 6
Nonredeemable Preferred Stock
Noncumulative Preferred Stock
Dec. 31, 2012
Fitchburg Gas and Electric Light Company
Series 8
Dec. 31, 2012
Fitchburg Gas and Electric Light Company
Series 5
Class of Stock [Line Items]                                            
Common stock, authorized shares       25,000,000 16,000,000                                  
Common stock, shares outstanding 13,841,400 13,780,601                                        
Common stock, share issued                               2,760,000 39,559 41,752 39,473      
Common stock price per share                               $ 25.25 $ 29.01          
Proceed from issuance of common stock $ 1,100,000 $ 66,800,000 $ 1,000,000                         $ 65,700,000 $ 1,100,000 $ 1,100,000 $ 1,000,000      
Common stock shares repurchase 2,969 6,368 8,765                                      
Repurchase expense 100,000 200,000 200,000                                      
Restricted stock available for awards                           677,500                
Restricted stock that may be awarded in any one calendar year to any one participant                           20,000                
Restricted stock vesting period                     4 years                      
Restricted stock vesting percentage annually                     25.00%                      
Restricted stock non-vested                     53,480 53,932                    
Restricted stock weighted average grant date fair value                     $ 25.99 $ 24.67                    
Share based compensation expense                     700,000 1,300,000 700,000                  
Unrecognized share based compensation                     700,000                      
Share compensation recognition period                     2.4                      
Forfeitures or cancellations under the stock plan                     0                      
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%              
Fair value of liabilities associated with fully vested RSUs that will be settled in cash                 200,000 100,000                        
Preferred Stock 200,000 200,000                                   200,000    
Dividend rate                                       6.00% 8.00% 5.125%
Redeemable, Cumulative Preferred Stock $ 0 $ 8,000 $ 8,600                                   $ 1,000,000 $ 800,000
Preferred Stock premium percentage                                           1.28%
Antidilutive securities excluded from computation of earnings per share           4,481 24,325 1,642