Commitments and Contingencies (Details Textual) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Long-term Purchase Commitment [Line Items]
Range of remaining compliance periods for tax credit syndication arrangements	less than one year to 12 years
Construction Contracts [Member]
Long-term Purchase Commitment [Line Items]
Commitments related to capital spending activities	$ 189.6
Commitments related to development, redevelopment and capital improvement activities [Member]
Long-term Purchase Commitment [Line Items]
Time Period of Long-term Purchase Commitment	12 months
Commitments related to operations [Member]
Long-term Purchase Commitment [Line Items]
Time Period of Long-term Purchase Commitment	one year or less