Derivative Instruments (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments
Change in value of undesignated interest rate swaps	$ 0	$ 82,200	$ (48,700)	$ 1,990,400
Reclassification from other comprehensive income to interest expense	0	238,800	2,600	389,500
Reclassification from other comprehensive income to interest expense - forecasted transaction probable not to occur	0	0	0	1,167,700
Included in interest expense	0	321,000	46,100	3,547,600
Loss on derivative instruments deferred into other comprehensive income/(loss)	0	0	0	(575,000)
Reclassification from other comprehensive income to interest expense	0	238,800	2,600	389,500
Reclassification from other comprehensive income to interest expense - forecasted transaction probable not to occur	0	0	0	1,167,700
Change in accumulated other comprehensive income	$ 0	$ 238,800	$ 2,600	$ 982,200