Securities - Realized Gains and Losses (Narrative) (Details) - USD ($)	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Marketable Securities [Abstract]
Equity securities, realized gain (loss)	$ 0
Available-for-sale securities pledged as collateral	$ 5,800,000	$ 4,300,000

Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

Name:	us-gaap_DebtSecuritiesAvailableForSaleRestricted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant