Summary Of Significant Accounting Policies (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense									$ 0	$ 0	$ 0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax										706	156,025
Discontinued Operation, Tax Effect of Discontinued Operation										4,441	(83,614)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest					$ 4,662	$ 289	$ 196	$ 0	0	5,147	72,411
Income tax expense									(78,086)	(67,449)	(72,240)
Net income from continuing operations	$ 40,103	$ 12,261	$ 27,287	$ 57,665	38,538	$ 13,043	$ 25,274	$ 46,462	137,316	123,317	192,277
Unfunded benefit obligation for pensions and other postretirement benefit plans	7,568				6,650				7,568	6,650
Unfunded benefit obligation for pensions and other postretirement benefit plans, tax	$ 4,075				$ 3,580				4,075	3,580
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax									0	0	732
Discontinued Operation, Tax Effect of Discontinued Operation									0	0	(272)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest									0	0	460
Realized gains on investment securities									0	0	(3)
Realized losses on investment securities									0	0	735
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									(1,413)	1,905	(5,622)
Amortization of net prior service cost									(1,171)	31	(1,094)
Amortization of net loss									(7,602)	2,623	(83,301)
Adjustment due to effects of regulation									7,360	(749)	78,773
Income tax expense									495	(667)	1,967
Net income from continuing operations									$ (918)	$ 1,238	$ (3,655)