Impairment of Real Estate and Impairment of Unconsolidated Entities (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of Real Estate	$ 0	$ 129,829,000	$ 0	$ 129,829,000
Impairment of Unconsolidated Entities	0	0	0	0
Avenue at Tower City Center [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of Real Estate	0	72,473,000	0	72,473,000
Terminal Tower [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of Real Estate	0	42,208,000	0	42,208,000
Post Office Plaza [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of Real Estate	0	14,378,000	0	14,378,000
Other [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of Real Estate	$ 0	$ 770,000	$ 0	$ 770,000