Noncontrolling Interests (Narrative) (Details)	Mar. 31, 2015
Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Operating Partnership (OP) Units (in shares)	16,242,774
Long-Term Incentive Plan (LTIP) Units (in shares)	1,845,626
Series Four Preferred Units (in shares)	12,667
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)	217,688
2013 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2013 MYLTIP (in shares)	309,818
MYLTIP 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIP (in shares)	476,320
2015 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIPS (in shares)	368,415