Segment Information (Schedule of Additional Business Segment Information) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 1,497,507	$ 1,495,274
Specialty Commercial Segment [Member]
Segment Reporting Information [Line Items]
Assets	1,117,057	1,082,804
Standard Commercial Segment [Member]
Segment Reporting Information [Line Items]
Assets	182,977	193,710
Personal Segment [Member]
Segment Reporting Information [Line Items]
Assets	137,108	164,685
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	$ 60,365	$ 54,075