Operating Leases (Details Textual) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($) ft² Location	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Leases [Abstract]
Lessee leasing agreements, operating leases, area under lease \| ft²	37,829
Number of office space locations \| Location	1
Operating lease expense excluding rent \| $	$ 0.4	$ 0.4	$ 0.4

The number of units (items of property) under operating lease arrangements.

No definition available.

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseNumberOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant