Organization and Summary of Significant Accounting Policies (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Summary of equipment held for sale measured at fair value on nonrecurring basis
Equipment held for sale	$ 7,265,684	$ 7,118,555
Gains (Losses)		2,206,253
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Summary of equipment held for sale measured at fair value on nonrecurring basis
Equipment held for sale
Significant Other Observable Inputs (Level 2) [Member]
Summary of equipment held for sale measured at fair value on nonrecurring basis
Equipment held for sale
Significant Unobservable Inputs (Level 3) [Member]
Summary of equipment held for sale measured at fair value on nonrecurring basis
Equipment held for sale	$ 7,265,684	$ 7,118,555