Provision for Impairment of Investment Properties - Impairment Indicators (Details) - property	Jun. 30, 2018	Jun. 30, 2017
Impaired Long-Lived Assets Held and Used [Line Items]
Number of properties for which indicators of impairment were identified	2	7
Number of properties for which an impairment charge was recorded	0	2
Number of properties held for sale with impairment indicators but not impaired	0	2
Remaining properties with impairment indicators but not impaired	2	3
Weighted average percentage by which projected undiscounted cash flows exceeded carrying value for remaining properties	38.00%	11.00%
Number of properties with impairment indicators which were subsequently sold		5