REDEEMABLE NONCONTROLLING INTERESTS (Details) $ in Thousands	6 Months Ended
	Oct. 31, 2016 USD ($) item
Redeemable Noncontrolling Interest [Line Items]
Balance at beginning of fiscal year	$ 7,522
Contributions	7,150
Balance at close of fiscal year	$ 8,585
Southgate - Minot, ND [Member]
Redeemable Noncontrolling Interest [Line Items]
Number of Joint Ventures with Buy Sell Options | item	1
Commitment Period for Joint Venture Acquisition	4 years
Balance at beginning of fiscal year	$ 7,522
Contributions	1,209
Net income	(146)
Balance at close of fiscal year	$ 8,585