Summary of Significant Accounting Policies Construction in Progress (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Construction in Progress [Line Items]
Internal direct construction costs capitalized related to development of properties and land holdings	$ 3,700,000	$ 4,700,000	$ 4,000,000
Interest Costs Capitalized	2,600,000	2,600,000	2,000,000
Salaries including bonuses and benefits, capitalized during the period	3,673,000	4,669,000	4,034,000
Development [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	156,000	57,000	0
Redevelopment [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	194,000	353,000	0
Tenant Improvements [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	$ 3,323,000	$ 4,259,000	$ 4,034,000