EQUITY - Equity Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017	Apr. 30, 2017
Equity
Noncontrolling interests - Operating Partnership (in shares)	14,168,000		14,168,000		15,617,000
Common stock outstanding (in shares)	120,035,000		120,035,000		121,199,000
Units converted to common stock (in shares)	450,000	0	1,400,000	0
Aggregate cost of stock conversion	$ 2,600		$ 8,600
Average price of shares issued (in dollars per share)	$ 5.77		$ 5.92
2015 Incentive Plan [Member]
Equity
Equity awards issued (in shares)	0	0	75,000	499,000
Total grant-date value shares issued			$ 445	$ 1,900