Derivative Financial Instruments (Schedule Of Fair Values Of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 26,746		$ 21,985
Liability Derivatives, Fair Value	26,313		10,997
Net unrealized gains on exchange traded futures and options contracts included in balance sheet			9,300
Net unrealized gains on cash flow hedges	17,100		3,300
Net unrealized gains on derivative financial instruments	1,300		2,800
Derivative Financial Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	26,738	[1]	21,956	[2]
Liability Derivatives, Fair Value	26,117	[3]	10,997
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	8		$ 29
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value
Liability Derivatives, Fair Value	$ 196

[1] At December 31, 2020, derivative financial instruments, as reflected on the balance sheet, includes net unrealized gains on exchange traded futures and options contracts of $3.3 million, which include $2.8 million of net unrealized gains on derivative financial instruments designated as cash flow hedging instruments.

[2] At December 31, 2021, derivative financial instruments, as reflected on the balance sheet, includes net unrealized losses on exchange traded futures and options contracts of $17.1 million, which include $1.3 million of net unrealized losses on derivative financial instruments designated as cash flow hedging instruments.

[3] At December 31, 2020, derivative financial instruments, as reflected on the balance sheet, includes net unrealized losses on exchange traded futures and options contracts of $9.3 million, none of which were designated as cash flow hedging instruments.