Summary Of Significant Accounting Policies (Reclassifications Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Income taxes	$ 31,942	$ 26,247
Other Comprehensive Income (Loss), Net of Tax	1,229	(246)
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	1,892	(378)
Income taxes	(663)	132
Other Comprehensive Income (Loss), Net of Tax	1,229	(246)
Amortization of net loss	311	273
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax	(3,642)	(3,688)
Adjustment due to effects of regulation	5,223	$ 3,037
OREGON | Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Adjustment due to effects of regulation	$ 2,100