Financial Instruments (Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Measurements, Recurring [Member]
Liabilities
Options sold	$ 301
Call Option \| Fair Value, Measurements, Recurring [Member]
Liabilities
Options sold	301	$ 0
Investments
Assets
Assets	5,142,589	4,729,270
Note receivable
Assets
Assets	0	5,725
Notes payable \| Unsecured Debt
Liabilities
Notes payable		415,253
Notes payable \| Unsecured Debt \| Fair Value, Measurements, Recurring [Member]
Liabilities
Notes payable	$ 413,378	$ 415,253

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Balance Type:	debit
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