Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 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	$ 3,171	$ 5,414
Notional value	68,653	132,176
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	0	(3,248)
Notional value of purchased credit derivatives offsetting written credit derivatives	$ 0	$ (81,637)
Derivative notional			$ (41,134)