EQUITY - Equity Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Apr. 30, 2018
Equity
Noncontrolling interests - Operating Partnership (in shares)	13,678,000		13,678,000		14,099,000
Common stock outstanding (in shares)	119,727,000		119,727,000		119,526,000
Units converted to common stock (in shares)			91,000	999,500
Aggregate cost of stock conversion			$ 482	$ 6,000
Average price of shares issued (in dollars per share)			$ 5.30	$ 5.98
2015 Incentive Plan [Member]
Equity
Equity awards issued (in shares)	13,000	0	56,000	75,000
Total grant-date value shares issued	$ 83		$ 347	$ 445
Exercise of Exchange Rights [Member]
Equity
Units converted to common stock (in shares)	217,000	0	331,000	0
Aggregate cost of stock conversion	$ 358		$ 649