CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Shares	Common Shares of Beneficial Interest, no par value	Accumulated Distributions In Excess of Net Income	Accumulated Other Comprehensive Income	Noncontrolling Interest	Series A Preferred Stock	Series A Preferred Stock Accumulated Distributions In Excess of Net Income	Series B Preferred Stock	Series B Preferred Stock Accumulated Distributions In Excess of Net Income	Series C Preferred Stock	Series C Preferred Stock Accumulated Distributions In Excess of Net Income
Beginning balance at Apr. 30, 2016	$ 718,262	$ 138,674	$ 922,084	$ (442,000)	$ 0	$ 99,504
Beginning balance (in shares) at Apr. 30, 2016			12,110
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to controlling interest and noncontrolling interests	30,947			43,347		(12,400)
Distributions – common shares and Units	(63,360)			(55,907)		(7,453)
Distributions - preferred shares	(10,546)						$ (1,403)	$ (1,403)	$ (9,143)	$ (9,143)
Shares issued and share-based compensation (in shares)			39
Shares issued and share-based compensation	358		$ 358
Redemption of Units for common shares (in shares)			50
Redemption of Units for common shares	0		$ 875			(875)
Redemption of Units for cash	(966)					(966)
Shares repurchased (in shares)			(79)
Shares repurchased	(33,253)	(27,317)	$ (4,501)	(1,435)
Contributions from nonredeemable noncontrolling interests – consolidated real estate entities	7,188					7,188
Conversion of equity of notes receivable from noncontrolling interests - consolidated real estate entities	(7,366)					(7,366)
Acquisition of nonredeemable noncontrolling interests - consolidated real estate entities	(4,874)		(9,893)			5,019
Other	(232)		(18)			(214)
Ending balance at Apr. 30, 2017	636,158	111,357	$ 908,905	(466,541)	0	82,437
Ending balance (in shares) at Apr. 30, 2017			12,120
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to controlling interest and noncontrolling interests	128,370			116,788		11,582
Change in fair value of derivatives	1,779				1,779
Distributions – common shares and Units	(37,785)			(33,689)		(4,096)
Distributions - preferred shares	(8,569)								$ (4,571)	$ (4,571)	$ (3,999)	$ (3,999)
Shares issued and share-based compensation (in shares)			10
Shares issued and share-based compensation	1,663		$ 1,663
Redemption of Units for common shares (in shares)			3
Redemption of Units for common shares	0		$ 34			(34)
Redemption of Units for cash	(8,775)					(8,775)
Shares repurchased (in shares)			(178)
Shares repurchased	(124,949)	(111,357)	$ (9,935)	(3,657)
Contributions from nonredeemable noncontrolling interests – consolidated real estate entities	619					619
Other (in shares)			(2)
Other	(403)		$ (570)			167
Issuance of Series C preferred shares	99,456	99,456
Ending balance at Apr. 30, 2018	687,563	99,456	$ 900,097	(395,669)	1,779	81,900
Ending balance (in shares) at Apr. 30, 2018			11,953
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to controlling interest and noncontrolling interests	(4,878)			(4,398)		(480)
Change in fair value of derivatives	(2,635)				(2,635)
Distributions – common shares and Units	(27,977)			(25,060)		(2,917)
Distributions - preferred shares	(4,547)										(4,548)	(4,548)
Shares issued and share-based compensation (in shares)			3
Shares issued and share-based compensation	1,042		$ 1,042
Redemption of Units for common shares (in shares)			33
Redemption of Units for common shares	0		$ 649			(649)
Redemption of Units for cash	(498)					(498)
Shares repurchased (in shares)			(42)
Shares repurchased	(2,172)		$ (2,172)
Acquisition of nonredeemable noncontrolling interests - consolidated real estate entities	(44)		$ (175)			131
Other (in shares)			(5)
Other	(207)		$ (207)
Distributions to nonredeemable noncontrolling interests - consolidated real estate entities	(2,432)					(2,432)
Conversion to equity of notes receivable from nonredeemable noncontrolling interests – consolidated real estate entities	(392)					(392)
Ending balance at Dec. 31, 2018	643,449	99,456	$ 899,234	(429,048)	(856)	74,663
Ending balance (in shares) at Dec. 31, 2018			11,942
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to controlling interest and noncontrolling interests	84,459			78,669		5,790
Change in fair value of derivatives	(6,751)				(6,751)
Distributions – common shares and Units	(36,410)			(32,996)		(3,414)
Distributions - preferred shares	(6,821)										$ (6,821)	$ (6,821)
Shares issued and share-based compensation (in shares)			11
Shares issued and share-based compensation	1,905		$ 1,905
Sale of common shares, net (in shares)			308
Sale of common shares, net	22,019		$ 22,019
Redemption of Units for common shares (in shares)			173
Redemption of Units for common shares	0		$ 7,823			(7,823)
Redemption of Units for cash	(8,147)					(8,147)
Shares repurchased (in shares)			(329)
Shares repurchased	(18,023)		$ (18,023)
Conversion of equity of notes receivable from noncontrolling interests - consolidated real estate entities	(220)					(220)
Acquisition of nonredeemable noncontrolling interests – consolidated real estate entities	4,529		$ 4,529
Other (in shares)			(7)
Other	(87)		$ (87)
Ending balance at Dec. 31, 2019	$ 679,902	$ 99,456	$ 917,400	$ (390,196)	$ (7,607)	$ 60,849
Ending balance (in shares) at Dec. 31, 2019			12,098