CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	PREFERRED STOCK [Member]	COMMON SHARES [Member]	ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME [Member]	NONREDEEMABLE NONCONTROLLING INTERESTS [Member]	Series A Preferred Stock [Member]	Series A Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series B Preferred Stock [Member]	Series B Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]	Series C Preferred Stock [Member]	Series C Preferred Stock [Member] PREFERRED STOCK [Member]	Series C Preferred Stock [Member] ACCUMULATED DISTRIBUTIONS IN EXCESS OF NET INCOME [Member]
Balance at Apr. 30, 2016	$ 718,262	$ 138,674	$ 922,084	$ (442,000)	$ 0	$ 99,504
Balance (in shares) at Apr. 30, 2016			121,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to controlling interests and noncontrolling interests	(2,813)			13,067		(15,880)
Distributions – common shares and units	(53,719)			(47,387)		(6,332)
Distributions - preferred shares	(8,260)						$ (1,403)	$ (1,403)	$ (6,857)	$ (6,857)
Shares issued and share-based compensation	1,756		$ 1,756
Shares issued and share-based compensation (in shares)			553
Redemption of units for common shares	0		$ 548			(548)
Redemption of units for common shares (in shares)			251
Shares repurchased	(28,752)	(27,317)		(1,435)
Contributions from nonredeemable noncontrolling interests – consolidated real estate entities	7,188					7,188
Distributions to nonredeemable noncontrolling interests – consolidated real estate entities	(159)					(159)
Acquisition of nonredeemable noncontrolling interests - consolidated real estate entities	(4,938)		$ (2,677)			(2,261)
Conversion to equity of notes receivable from nonredeemable noncontrolling interests - consolidated real estate entities	(7,366)					(7,366)
Other	0		$ 24			(24)
Other (in shares)			(6)
Balance at Jan. 31, 2017	621,199	111,357	$ 921,735	(486,015)	0	74,122
Balance (in shares) at Jan. 31, 2017			121,889
Balance at Apr. 30, 2017	636,094	111,357	$ 916,121	(466,541)		75,157
Balance (in shares) at Apr. 30, 2017			121,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to controlling interests and noncontrolling interests	152,325			137,662		14,663
Other comprehensive income - derivative instrument	359				359
Distributions – common shares and units	(28,390)			(25,284)		(3,106)
Distributions - preferred shares	(6,864)								$ (4,571)	$ (4,571)	$ (2,293)		$ (2,293)
Shares issued and share-based compensation	1,216		$ 1,216
Shares issued and share-based compensation (in shares)			75
Series C preferred shares issued											$ 99,456	$ 99,456
Redemption of units for cash	(8,577)					(8,577)
Shares repurchased	(122,149)	(111,357)	$ (7,135)	(3,657)
Shares repurchased (in shares)			(1,232)
Contributions from nonredeemable noncontrolling interests – consolidated real estate entities	239					239
Distributions to nonredeemable noncontrolling interests – consolidated real estate entities	(46)					(46)
Conversion to equity of notes receivable from nonredeemable noncontrolling interests - consolidated real estate entities	(246)					(246)
Other	(29)		$ (29)
Other (in shares)			7
Balance at Jan. 31, 2018	$ 723,388	$ 99,456	$ 910,173	$ (364,684)	$ 359	$ 78,084
Balance (in shares) at Jan. 31, 2018			120,035