Financial Commitments (Summary Of Information Related To The Liability And Equity Components Of The Convertible Notes) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2019	Jun. 15, 2016
Debt Instrument [Line Items]
Reacquisition of conversion option from repurchase of notes, net of tax	$ (764,000)
Deferred taxes	(81,271,000)	$ (68,856,000)
Convertible Notes
Debt Instrument [Line Items]
Principal				$ 200,000,000
Liability Component | Convertible Notes
Debt Instrument [Line Items]
Principal	69,918,000		$ 200,000,000
Conversion feature	(46,800,000)
Allocated debt issuance costs	(5,051,000)
Amortization and extinguishment of discount and debt issuance costs (non-cash interest expense)	49,811,000
Net carrying amount	67,878,000
Equity Component | Convertible Notes
Debt Instrument [Line Items]
Allocated debt issuance costs	(1,543,000)
Net carrying amount	25,678,000
Conversion feature	46,800,000		$ 46,800,000
Reacquisition of conversion option from repurchase of notes, net of tax	(764,000)
Deferred taxes	$ (18,815,000)