Quarterly report pursuant to Section 13 or 15(d)

Fair Value of Other Securities (Details Textual)

v2.4.0.8
Fair Value of Other Securities (Details Textual) (USD $)
Share data in Millions, unless otherwise specified
 3 Months Ended 6 Months Ended 1 Months Ended 3 Months Ended
Jun. 30, 2013
May 31, 2012
Jun. 30, 2013
May 31, 2012
Nov. 30, 2011
High Sierra Energy [Member]
Aug. 31, 2012
High Sierra Energy [Member]
Dec. 31, 2012
Lightfoot Capital Partners LP [Member]
Dec. 31, 2012
Vantacore Partners LP [Member]
Schedule of Equity Method Investments [Line Items]                
Equity Method Investment, Ownership Percentage             6.70% 11.10%
Fair Value of Financial Instruments (Textual) [Abstract]                
Consideration paid in cash for acquisition         $ 9,400,000      
Consideration paid in newly issued units         1.2      
Gains and losses on sales of securities 0 0 (434,941) 0   15,800,000    
Fair Value of Financial Instruments (Additional Textual) [Abstract]                
Transfers between levels 0 0            
Minimum period for releasing of escrow receivable 14 months              
Remaining amount of escrow receivable $ 699,000