Organization of the Parent Company and The Operating Partnership (Details) ft² in Millions	Jun. 30, 2015 a ft² property real_estate_investment	Jun. 30, 2014 ft²
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	9
Parent Company [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the Operating Partnership	99.10%
Net Rentable Square Feet | ft²	25.2
Area Owned by Company of Undeveloped Parcels Of Land | a	430
Area Of Additional Undeveloped Parcels Of Land With Option to Purchase | a	63
Total Potential Development Capacity | ft²	7.2
Unconsolidated Real Estate Ventures [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	5.6	5.9
Number of Unconsolidated Real Estate Ventures | real_estate_investment	18
Wholly-owned Management Company Subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	33.0
Third Parties and Real Estate Ventures [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	7.8
Total Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	199
Office Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	167
Industrial Facilities [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	20
Mixed Use Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	5
Retail Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	1
Core Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	193
Development Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	4
Redevelopment Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	1
Re-entitlement Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	1
Wholly Owned Properties [Member] | Parent Company [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	25.2