DISCONTINUED OPERATIONS, Properties Disposed of or Held for Sale (Details) - property	3 Months Ended	6 Months Ended	12 Months Ended
	Oct. 31, 2016	Oct. 31, 2016	Apr. 30, 2016
Discontinued Operations, Disposed of by Sale [Member] | Office [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties classified as held for sale in discontinued operations			48
Discontinued Operations, Disposed of by Sale [Member] | Retail [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties classified as held for sale in discontinued operations			17
Discontinued Operations, Disposed of by Sale [Member] | Commercial Healthcare [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties classified as held for sale in discontinued operations			1
Discontinued Operations, Disposed of by Sale [Member] | Senior Housing properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold	8
Discontinued Operations, Held-for-sale [Member] | Senior Housing properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties classified as held for sale in discontinued operations		26	34