Commitments and Contingencies (Details Textual) $ in Millions	1 Months Ended	6 Months Ended
	May 31, 2017 parties	Jun. 30, 2018 USD ($)
Long-term Purchase Commitment [Line Items]
Number of potentially responsible parties, environmental remediation | parties	4
Commitments related to development, redevelopment and capital improvement activities [Member]
Long-term Purchase Commitment [Line Items]
Commitments related to capital spending activities | $		$ 118.0
Time Period of Long-term Purchase Commitment		12 months
Maximum [Member] | Commitments related to operations [Member]
Long-term Purchase Commitment [Line Items]
Time Period of Long-term Purchase Commitment		1 year