Noncontrolling Interests - Fund II Assets (Details) - Jun. 30, 2015		Total
Hayden Ferry Lakeside I
Noncontrolling Interest [Line Items]
Location		Phoenix, AZ
Company's Ownership %		30.00%
Hayden Ferry Lakeside II
Noncontrolling Interest [Line Items]
Location		Phoenix, AZ
Company's Ownership %		30.00%
Hayden Ferry Lakeside III
Noncontrolling Interest [Line Items]
Location		Phoenix, AZ
Company's Ownership %		70.00%
Hayden Ferry Lakeside IV and adjacent garage
Noncontrolling Interest [Line Items]
Location		Phoenix, AZ
Company's Ownership %		30.00%
245 Riverside (1)
Noncontrolling Interest [Line Items]
Location	[1]	Jacksonville, FL
Company's Ownership %	[1]	30.00%
3344 Peachtree
Noncontrolling Interest [Line Items]
Location		Atlanta, GA
Company's Ownership %		33.00%
Two Liberty Place
Noncontrolling Interest [Line Items]
Location		Philadelphia, PA
Company's Ownership %		19.00%

[1] On July 17, 2015, the Company sold 245 Riverside. See "Note 13 – Subsequent Events."