Revenue from Contracts with Customers Revenue from Contracts with Customers (Schedule of Consumer Brokerage Services) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Consumer Brokerage Services [Line Items]
Brokerage Commissions Revenue	$ 15,807	$ 14,630	$ 13,784
Commission Income [Member]
Consumer Brokerage Services [Line Items]
Brokerage Commissions Revenue	8,956	8,400	8,170
Managed Account Services [Member]
Consumer Brokerage Services [Line Items]
Brokerage Commissions Revenue	$ 6,851	$ 6,230	$ 5,614

Amount of commission revenue from buying and selling securities on behalf of customers.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 20
-Section 05
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=68070981&loc=d3e40544-110947

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(a),(b))
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Name:	us-gaap_BrokerageCommissionsRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration