| 
           Business Acquisitions and Related Transactions - Business Acquisition (Details) (USD $) 
         | 
        3 Months Ended | 9 Months Ended | 9 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|---|---|
| 
           Sep. 30, 2013 
         | 
        
           Sep. 30, 2012 
         | 
        
           Sep. 30, 2013 
         | 
        
           Sep. 30, 2012 
         | 
        
           Dec. 31, 2012 
         | 
        
           Sep. 30, 2013
 
          ESP [Member] 
         | 
        
           Sep. 30, 2013
 
          Ennovate [Member] 
         | 
        
           Dec. 31, 2012
 
          FAME [Member] 
         | 
      |
| Business Acquisition [Line Items] | ||||||||
| Cash | $ 1,291,697 | $ 0 | $ 809,557 | |||||
| Accounts receivable and accounts receivable retainage | 360,924 | 445,769 | 320,997 | |||||
| Costs and estimated earnings in excess of billings | 546,608 | 110,987 | 0 | |||||
| Prepaid expenses and other current assets | 0 | 1,710 | 107,715 | |||||
| Property and equipment and project assets | 75,054 | 62,898 | 43,115 | |||||
| Goodwill | 55,615,137 | 55,615,137 | 48,968,390 | 5,089,049 | 921,128 | 1,886,945 | ||
| Intangible assets | 3,087,509 | 610,000 | 2,099,990 | |||||
| Other assets | 0 | 0 | 100 | |||||
| Accounts payable | (47,625) | (313,976) | (5,713) | |||||
| Accrued liabilities | (606,938) | 0 | (617,731) | |||||
| Billings in excess of cost and estimated earnings | 0 | (30,431) | (158,025) | |||||
| Other liabilities | (967,065) | 0 | 0 | |||||
| Purchase price | 8,829,213 | 1,808,085 | 4,486,950 | |||||
| Total, net of cash received | 599,375 | 3,677,393 | 9,944,976 | 3,677,393 | 7,537,516 | 1,808,085 | 3,677,393 | |
| Total fair value of consideration | $ 8,829,213 | $ 1,808,085 | $ 4,486,950 | |||||
| X | ||||||||||
| 
             
- Definition 
          Business Acquisition, Purchase Price Allocation, Current Assets, Costs and Estimated Earnings in Excess of Billings No definition available. 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Business Acquisition, Purchase Price Allocation, Current Liabilities, Billings in Excess of Cost and Estimated Earnings No definition available. 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Business Acquisitions Purchase Price Allocation, Other Liablitities No definition available. 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Details 
          
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of acquisition cost of a business combination allocated to an identifiable intangible asset that will be amortized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of cash and cash equivalents acquired in a business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of acquisition cost of a business combination allocated to prepaid expenses and other current assets. Does not include amounts allocated to cash and cash equivalents, marketable securities, receivables, inventory, and assets not to be used. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of acquisition cost of a business combination allocated to receivables. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of acquisition cost of a business combination allocated to accounts payable of the acquired entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of acquisition cost of a business combination allocated to accrued expenses of the acquired entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Amount of acquisition cost of a business combination allocated to other noncurrent assets not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The amount of acquisition cost of a business combination allocated to property, plant and equipment to be used in ongoing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          This element represents the acquisition-date fair value of the total consideration transferred which consists of the sum of the acquisition-date fair values of the assets transferred by the acquirer, the liabilities incurred by the acquirer to former owners of the acquiree, and the equity interests issued by the acquirer. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  |