Reconciliation of Segment Operating Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Reconciliation Of Segment Operating Income Details
Total operating income									$ 7,796,053	$ 8,442,056
Interest expense, net									1,327,160	868,507
Other (income) expense, net									(24,404)	76,846
Consolidated income before taxes									6,493,297	7,496,703
Net income	$ (655,000)	$ 1,202,000	$ 2,846,000	$ 659,000	$ 545,000	$ 1,473,000	$ 3,267,000	$ 565,000	$ 4,052,479	$ 5,850,998