Financial Derivatives (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Spread on written credit derivatives		3.10%
Written credit derivative spread threshold	20.00%	20.00%
Credit Default Swap, Selling Protection [Member]
Derivative [Line Items]
Total net up-front payments received	$ (4,600)	$ (1,600)
Minimum
Derivative [Line Items]
Spread on written credit derivatives	0.50%
Upfront points on written credit derivative in excess of threshold	46.3	46.3
Maximum
Derivative [Line Items]
Spread on written credit derivatives	4.38%
Upfront points on written credit derivative in excess of threshold	46.3	88.8