Summary Of Significant Accounting Policies (Accumulated Other Comprehensive Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax											$ (156,025)		$ (13,177)		$ (3,494)
Discontinued Operation, Tax Effect of Discontinued Operation											83,614		5,216		1,497
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(1,639)		55	(69,312)	(1,515)	(1,140)		(3,448)	(1,491)	(1,882)	(72,411)		(7,961)		(1,997)
Income Tax Expense (Benefit)											(72,240)		(58,014)		(39,764)
Net income from continuing operations	32,243		10,471	100,582	48,981	31,532		11,931	25,730	43,101	192,277		112,294		78,800
Unfunded benefit obligation for pensions and other postretirement benefit plans	(7,888)					(4,233)					(7,888)		(4,233)
Unrealized gain (loss) on securities available for sale - net of taxes of $0 and $(936), respectively (1)	0	[1]				(1,586)	[1]				0	[1]	(1,586)	[1]
Total accumulated other comprehensive loss	(7,888)					(5,819)					(7,888)		(5,819)
Unfunded benefit obligation for pensions and other postretirement benefit plans, tax	(4,247)					(2,281)					(4,247)		(2,281)
Unrealized gain on securities available for sale, tax	0					(936)					0		(936)
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]
Other Comprehensive Income Loss Reclassification Adjustment From AOCI For Realized Losses on Sale of Securities Before Tax											(735)	[2]	0	[2]
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax											(732)		19
Discontinued Operation, Tax Effect of Discontinued Operation											272		(7)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest											(460)		12
Other Income											3	[2]	19	[2]
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											5,622		(4,052)
Income Tax Expense (Benefit)											(1,967)		1,418
Net income from continuing operations											3,655		(2,634)
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax											1,094	[3]	(10,681)	[3]
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax											83,301	[3]	(142,794)	[3]
Other Comprehensive Income Loss Adjustment From AOCI Pension And Other Postretirement Benefit Plans For Net Prior Service Cost , Adjustment Due to Effects of Regulation											$ (78,773)	[3]	$ 149,423	[3]
Minimum [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Lessee Leasing Arrangements, Operating Leases, Term of Contract											1 year
Maximum [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Lessee Leasing Arrangements, Operating Leases, Term of Contract											45 years

[1] This entire balance was related to Ecova, which was disposed of as of June 30, 2014.

[2] These amounts were included as part of net income from discontinued operations for all periods presented (see Note 5 for additional details).

[3] These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 10 for additional details).