Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Credit Default Swap, Selling Protection [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net		$ 4,339
Fair Value	$ 4,718
Notional value	134,377
Derivative notional		(98,586)
Credit Default Swap, Buying Protection [Member]
Credit Derivatives [Line Items]
Credit Risk Derivatives, at Fair Value, Net		284
Fair Value of Purchased Credit Derivatives Offsetting Written Credit Derivatives	(2,581)
Notional value of purchased credit derivatives offsetting written credit derivatives	$ (84,029)
Derivative notional		$ (41,134)