CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)
Net cash provided by operating activities	$ 3,843,490	$ 8,552,481
Cash flows from investing activities
Additions to property, plant and equipment and construction in progress	(710,823)	(1,816,397)
Proceeds from asset dispositions	450	443,500
Proceeds from sale of discontinued operations, net of cash provided	0	6,706,234
Acquisition of noncontrolling interest in Aerex	(8,500,000)	0
Collections on loans receivable	0	734,980
Net cash provided by (used in) investing activities	(9,210,373)	6,068,317
Cash flows from financing activities
Dividends paid to common shareholders	(2,564,980)	(2,551,153)
Dividends paid to preferred shareholders	(5,738)	(5,747)
Repurchase of redeemable preferred stock	0	(24,096)
Principal repayments on long-term debt	(13,158)	0
Proceeds received from exercise of stock options	4,418	7,123
Net cash used in financing activities	(2,579,458)	(2,573,873)
Net increase (decrease) in cash and cash equivalents	(7,946,341)	12,046,925
Cash and cash equivalents at beginning of period	42,902,669	31,337,477
Cash and cash equivalents at end of period	34,956,328	43,384,402
Cash and cash equivalents at end of period	34,956,328	41,878,723
Restricted cash at end of period	0	1,505,679
Cash and cash equivalents and restricted cash at end of period	34,956,328	43,384,402
Interest paid in cash	5,344	1,482
Non-cash transactions:
Dividends declared but not paid	1,288,154	1,280,139
Transfers from (to) inventory to (from) property, plant and equipment and construction in progress	(49,133)	223,136
Transfers from construction in progress to property, plant and equipment	1,400,811	6,916,301
Right-of-use assets obtained in exchange for new operating lease liabilities	78,003	$ 4,850,902
Purchase of equipment through issuance of long-term debt	$ 122,292