Summary Of Significant Accounting Policies (Summary Of Currency Exchange Rates) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Australian Dollar [Member] | Spot Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.7030	0.7046	0.7815
Australian Dollar [Member] | Average Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6954	0.7479	0.7670
New Zealand Dollar [Member] | Spot Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6745	0.6711	0.7100
New Zealand Dollar [Member] | Average Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6593	0.6930	0.7111