CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (unaudited) - USD ($) shares in Thousands, $ in Thousands	Series A Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series A Preferred Stock [Member]	Series B Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series B Preferred Stock [Member]	Series C Preferred Stock [Member] PREFERRED SHARES [Member]	Series C Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series C Preferred Stock [Member]	PREFERRED SHARES [Member]	Common Shares and Limited Partnership Units [Member]	ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	NONREDEEMABLE NONCONTROLLING INTERESTS [Member]	Total
Balance at Apr. 30, 2016								$ 138,674	$ 922,084	$ (442,000)	$ 99,504	$ 718,262
Balance (in shares) at Apr. 30, 2016								5,750	121,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to controlling interests and noncontrolling interests										(10,043)	(18,116)	(28,159)
Distributions - common shares and units										(31,556)	(4,234)	(35,790)
Distributions - preferred shares	$ (1,186)	$ (1,186)	$ (4,571)	$ (4,571)								(5,757)
Shares issued and share-based compensation									$ 1,218			1,218
Shares issued and share-based compensation (in shares)									553
Redemption of units for common shares									$ 134		(134)
Redemption of units for common shares (in shares)									57
Contributions from nonredeemable noncontrolling interests - consolidated real estate entities											7,150	7,150
Distributions to nonredeemable noncontrolling interests - consolidated real estate entities											(155)	(155)
Acquisition of nonredeemable noncontrolling interests – consolidated real estate entities									$ (2,677)		(2,261)	(4,938)
Other											(615)	(615)
Balance at Oct. 31, 2016								$ 138,674	$ 920,759	(489,356)	81,139	651,216
Balance (in shares) at Oct. 31, 2016								5,750	121,701
Balance at Apr. 30, 2017								$ 111,357	$ 916,121	(466,541)	75,157	636,094
Balance (in shares) at Apr. 30, 2017								4,600	121,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to controlling interests and noncontrolling interests										1,557	(1,328)	229
Distributions - common shares and units										(16,881)	(2,089)	(18,970)
Distributions - preferred shares			$ (4,571)	$ (4,571)		$ (527)	$ (527)					(5,098)
Shares issued and share-based compensation									$ 844			844
Shares issued and share-based compensation (in shares)									75
Series C preferred shares issued					$ 99,467		$ 99,467
Series C preferred shares issued (in shares)					4,118
Redemption of units for cash											(5,982)	(5,982)
Shares repurchased								$ (111,357)	$ (6,253)	(3,649)		(121,259)
Shares repurchased (in shares)								(4,600)	(1,080)
Contributions from nonredeemable noncontrolling interests - consolidated real estate entities											239	239
Distributions to nonredeemable noncontrolling interests - consolidated real estate entities											(41)	(41)
Other									$ (29)			(29)
Other (in shares)									(5)
Balance at Oct. 31, 2017								$ 99,467	$ 910,683	$ (490,612)	$ 65,956	$ 585,494
Balance (in shares) at Oct. 31, 2017								4,118	120,189