|**Accounts Receivable**              | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|------------------------------------ | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Accounts Receivable [Abstract]**   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Accounts Receivable                  | Note 5 –Accounts Receivable
		
		December 31,2014
				
				2013Billed utility revenue
				$
				55,537
				$
				56,178Unbilled revenue
				
				35,566
				
				33,346Other
				
				11,261
				
				9,593102,364
				
				99,117Less allowance for doubtful accounts
				
				5,365
				
				4,413Net accounts receivable
				$
				96,999
				$
				94,704
		
		The Company’s utility customers are located principally in the following states:47% in Pennsylvania,16% in Ohio,10% in North Carolina,8% in Texas, and7% in Illinois.No single customer accounted for more than one percent of the Company's regulated operating revenues during the years ended December 31,2014, 2013, and2012.  The following table summarizes the changes in the Company’s allowance for doubtful accounts:
		
		2014
				2013
				2012Balance at January 1,
				$
				4,413
				$
				4,299
				$
				4,485Amounts charged to expense
				
				5,838
				
				4,708
				
				4,785Accounts written off
				
				(6,120)
				
				(5,884)
				
				(5,935)Recoveries of accounts written off
				
				1,234
				
				1,290
				
				964Balance at December 31,
				$
				5,365
				$
				4,413
				$
				4,299
|                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|                                     | December 31,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
|                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Billed utility revenue               | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Unbilled revenue                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Other                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Less allowance for doubtful accounts |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Net accounts receivable              | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|                                     | 2014                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Balance at January 1,                | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Amounts charged to expense           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Accounts written off                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Recoveries of accounts written off   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|Balance at December 31,              | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

X- Details**Name:**
                    us-gaap_AccountsReceivableNetAbstract**Namespace Prefix:**
                    us-gaap_**Data Type:**
                    xbrli:stringItemType**Balance Type:**
                    na**Period Type:**
                    duration X- DefinitionThe entire disclosure for financing receivables. Examples of financing receivables include, but are not limited to, loans, trade accounts receivables, notes receivable, credit cards, and receivables relating to a lessor's right(s) to payment(s) from a lease other than an operating lease that is recognized as assets.+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 55 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=32702940&loc=SL6953791-111525Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e4975-111524+ Details**Name:**
                    us-gaap_FinancingReceivablesTextBlock**Namespace Prefix:**
                    us-gaap_**Data Type:**
                    nonnum:textBlockItemType**Balance Type:**
                    na**Period Type:**
                    duration