EQUITY METHOD INVESTMENTS - Schedule of Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments
Revenue	$ 46,728	$ 55,819	$ 35,604	$ 36,970	$ 65,604	$ 73,300	$ 50,693	$ 47,188	$ 175,121		$ 236,785
Operating loss									(9,175)		7,291
Net loss									(7,277)		7,656
Net loss attributable to Air T, Inc. stockholders									$ (723)		$ (910)
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments
Revenue										$ 91,245		$ 108,751
Gross Profit										4,589		7,570
Operating loss										(10,551)		(2,653)
Net loss										(1,960)		(3,645)
Net loss attributable to Air T, Inc. stockholders										$ (760)		$ (887)