Maintenance Reserves and Accrued Maintenance Costs, Additions to and Deductions from Accrued Maintenance Costs (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accrued maintenance cost [Roll Forward]
Balance, beginning of period	$ 878,700	$ 1,013,400
Additions [Abstract]
Charged to expense	8,765,000	4,082,100
Capital equipment	482,900	52,200
Accrued claims related to refundable maintenance reserves	745,600	763,900
Prepaid maintenance and other	1,114,000	239,700
Total additions	11,107,500	5,137,900
Deductions [Abstract]
Payments	8,297,700	4,614,900
Other	914,400	657,700
Total deductions	9,212,100	5,272,600
Net increase/(decrease) in accrued maintenance costs	1,895,400	(134,700)
Balance, end of period	$ 2,774,100	$ 878,700