Segment Information (Schedule of Additional Business Segment Information) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 1,270,791	$ 1,231,126
Specialty Commercial Segment [Member]
Segment Reporting Information [Line Items]
Assets	854,360	810,133
Standard Commercial Segment [Member]
Segment Reporting Information [Line Items]
Assets	163,478	162,152
Personal Segment [Member]
Segment Reporting Information [Line Items]
Assets	230,397	232,441
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	$ 22,556	$ 26,400