RELATED PARTY TRANSACTIONS (Details)	12 Months Ended
	Apr. 30, 2017 USD ($) loan	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)
BANKING SERVICES [Abstract]
Interest and fees paid amount		$ 2,200,000	$ 1,700,000
Mortgages Payable [Member]
BANKING SERVICES [Abstract]
Variable interest rate (in hundredths)	4.71%	4.54%
Multi bank Line of Credit [Member]
BANKING SERVICES [Abstract]
Maximum borrowing capacity	$ 100,000,000
First International Bank & Trust [Member]
BANKING SERVICES [Abstract]
Bank service and other fees charged	900	$ 500	500
Interest and fees paid amount	$ 2,400,000	2,500,000	2,000,000
First International Bank & Trust [Member] | Mortgages Payable [Member]
BANKING SERVICES [Abstract]
Number of mortgage loans outstanding | loan	2
First International Bank & Trust [Member] | Multi bank Line of Credit [Member]
BANKING SERVICES [Abstract]
Maximum borrowing capacity	$ 11,000,000
Interest paid	106,000	186,000	245,000
Bank services charges and fee	56,000	$ 77,000	$ 40,000
Compensating balance	6,000,000
Non interest bearing account	1,500,000
Interest bearing account	$ 4,500,000
Percentage interest on deposited amount (in hundredths)	0.20%
Renaissance Heights I - Williston ND [Member] | First International Bank & Trust [Member] | Mortgages Payable [Member]
BANKING SERVICES [Abstract]
Original principal balance	$ 43,000,000
Variable interest rate (in hundredths)	5.24%
Fixed interest rate (in hundredths)	4.04%
Interest paid	$ 1,700,000
Commons at Southgate - Minot, ND [Member] | First International Bank & Trust [Member] | Mortgages Payable [Member]
BANKING SERVICES [Abstract]
Original principal balance	27,000,000
Interest paid	$ 579,000