Segment Information (Schedule of Additional Business Segment Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Assets	$ 1,328,731	$ 1,264,894
Specialty Commercial Segment [Member]
Segment Reporting Information [Line Items]
Assets	936,876	858,262
Standard Commercial Segment [Member]
Segment Reporting Information [Line Items]
Assets	183,344	158,881
Personal Segment [Member]
Segment Reporting Information [Line Items]
Assets	167,406	226,431
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	$ 41,105	$ 21,320