Fair Value (Fair Value Of Assets And Liabilities Measured On Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	$ 66,849		$ 89,132
Securities available for sale:			69,361
Liability	103,191		89,675
Cash and cash equivalents	10,391		82,574		91,979	75,464
Fixed Income Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,000		700
Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency derivatives			1
Interest rate swaps	8,253		33,543
Money Market Funds, Fair Value			11,180
Funds held in trust account of Spokane Energy	1,600		1,600
Total	22,807		127,991
Foreign currency derivative liabilities at fair value	280		0
Interest rate swaps	16,708
Total	35,957		29,231
Fair Value, Measurements, Recurring [Member] | Energy commodity derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	5,027		3,876
Liability	4,282		12,796
Fair Value, Measurements, Recurring [Member] | Power Option Agreement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liability	362		775
Fair Value, Measurements, Recurring [Member] | Natural Gas Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	0
Liability	1,471		1,219
Fair Value, Measurements, Recurring [Member] | Power Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	0		0
Liability	12,854		14,441
Fair Value, Measurements, Recurring [Member] | U.S. Government Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			61,078
Fair Value, Measurements, Recurring [Member] | Municipal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			3,518
Fair Value, Measurements, Recurring [Member] | Corporate fixed income - financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			3,000
Fair Value, Measurements, Recurring [Member] | Corporate fixed income - industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			765
Fair Value, Measurements, Recurring [Member] | Certificates of deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			1,000
Fair Value, Measurements, Recurring [Member] | Fixed Income Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	1,831	[1]	1,960	[1]
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	6,096	[1]	6,470	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money Market Funds, Fair Value			11,180
Funds held in trust account of Spokane Energy	1,600		1,600
Total	9,527		21,210
Total	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Income Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	1,831	[1]	1,960	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	6,096	[1]	6,470	[1]
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency derivatives			7
Interest rate swaps	13,300		33,543
Total	65,991		158,154
Foreign currency derivative liabilities at fair value	280		6
Interest rate swaps	34,485
Total	87,646		72,901
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Energy commodity derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	52,691		55,243
Liability	52,881		72,895
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Government Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			61,078
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Municipal [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			3,518
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate fixed income - financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			3,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate fixed income - industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			765
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Certificates of deposits [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available for sale:			1,000
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	858		339
Total	15,545		16,774
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Power Option Agreement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Liability	362		775
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Natural Gas Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	58
Liability	1,529		1,219
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Power Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	800		339
Liability	13,654		14,780
Fair Value, Measurements, Recurring [Member] | Netting [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Foreign currency derivatives			(6)	[2]
Interest rate swaps	(5,047)
Total	(53,569)	[2]	(51,712)	[2]
Foreign currency derivative liabilities at fair value	0		(6)
Interest rate swaps	(17,777)
Total	(67,234)	[2]	(60,444)	[2]
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Energy commodity derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	(47,664)	[2]	(51,367)	[2]
Liability	(48,599)	[2]	(60,099)	[2]
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Natural Gas Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	(58)
Liability	(58)		0	[2]
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Power Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	(800)		(339)	[2]
Liability	$ (800)		$ (339)	[2]

[1] These assets are trading securities and are included in other property and investments-net on the Condensed Consolidated Balance Sheets.

[2] The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties.