Financial Instruments (Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Investments
Assets
Assets	$ 5,039,614	$ 5,142,589
Fair Value, Measurements, Recurring
Liabilities
Liabilities	569	301
Fair Value, Measurements, Recurring \| Options sold
Liabilities
Liabilities	$ 569	$ 301

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant