DERIVATIVE INSTRUMENT (Details) - USD ($)	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Derivative [Line Items]
Gain recognized in other comprehensive income (loss)	$ 1,600,000
Gain reclassified from AOCI into income	34,178,000	$ 34,314,000	$ 28,417,000
Cash flow hedge gain (loss) to be reclassified within twelve months	21,000
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative instrument - interest rate swap	1,800,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount	70,000,000
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative [Line Items]
Gain reclassified from AOCI into income	$ 152,000