Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Credit Default Swap, Selling Protection [Member]
Credit Derivatives [Line Items]
Fair Value of Written Credit Derivatives, Net	$ 2,598	$ (4,339)
Notional value	89,230	98,586
Credit Default Swap, Buying Protection [Member]
Credit Derivatives [Line Items]
Fair Value of Written Credit Derivatives, Net	(167)	(284)
Notional value	$ 13,153	$ 41,134

Fair value of credit risk derivative asset after deduction of credit risk derivative liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5708775-113959

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