Operations In Foreign Currency (Summary Of Currency Exchange Rates) (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Australian Dollar [Member] | Spot Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.7009	0.7399	0.7009	0.7399	0.7046
Australian Dollar [Member] | Average Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.7001	0.7569	0.7062	0.7715	0.7479
New Zealand Dollar [Member] | Spot Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6711	0.6773	0.6711	0.6773	0.6711
New Zealand Dollar [Member] | Average Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6626	0.7046	0.6721	0.7161	0.6930