Indebtedness (Parentheticals) (Details 1)	9 Months Ended
Sep. 30, 2018
Debt Disclosure [Abstract]
Unused commitment fee	0.30%
Letter of credit fee	1.75%

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

No definition available.

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration