Summary Of Significant Accounting Policies (Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	13,177
Discontinued Operation, Tax Effect of Discontinued Operation									4,441	(83,614)	(5,216)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 4,662	$ 289	$ 196	$ 0	$ 1,639	$ (55)	$ 69,312	$ 1,515	5,147	72,411	7,961
Income tax expense									67,449	72,240	58,014
Net income	38,538	$ 13,043	$ 25,274	$ 46,462	32,243	$ 10,471	$ 100,582	$ 48,981	123,317	192,277	$ 112,294
Unfunded benefit obligation for pensions and other postretirement benefit plans	6,650				7,888				6,650	7,888
Unfunded benefit obligation for pensions and other postretirement benefit plans, tax	$ 3,580				$ 4,247				3,580	4,247
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	(732)
Discontinued Operation, Tax Effect of Discontinued Operation									0	272
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest									0	(460)
Realized gains on investment securities									0	3
Realized losses on investment securities									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									(1,905)	5,622
Income tax expense									667	(1,967)
Net income									(1,238)	3,655
Amortization of net prior service cost									(31)	1,094
Amortization of net loss									(2,623)	(83,301)
Adjustment due to effects of regulation									$ 749	$ (78,773)