Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Activities:
Net income	$ 48,981	$ 43,101
Non-cash items included in net income:
Depreciation and amortization	34,582	31,618
Provision for deferred income taxes	1,453	1,120
Power and natural gas cost amortizations (deferrals), net	(8,041)	2,545
Amortization of debt expense	953	947
Amortization of investment in exchange power	613	613
Stock-based compensation expense	1,551	1,464
Equity-related AFUDC	(2,034)	(1,391)
Pension and other postretirement benefit expense	7,415	10,949
Amortization of Spokane Energy contract	3,007	2,764
Other	4,212	1,118
Contributions to defined benefit pension plan	(11,000)	(14,670)
Changes in working capital components:
Accounts and notes receivable	17,257	2,432
Materials and supplies, fuel stock and natural gas stored	12,141	17,137
Other current assets	30,333	(14,288)
Accounts payable	(11,065)	(20,778)
Other current liabilities	26,540	40,698
Net cash provided by operating activities	156,898	105,379
Investing Activities:
Utility property capital expenditures (excluding equity-related AFUDC)	(59,725)	(70,645)
Other capital expenditures	(3,929)	(819)
Federal grant payments received	876	1,567
Decrease (increase) In Money Market Funds Held For Clients	(9,346)	2,816
Purchase of securities available for sale	0	(24,956)
Sale and maturity of securities available for sale	11,403	7,000
Other	24	(1,649)
Net cash used in investing activities	(60,697)	(86,686)
Financing Activities:
Net increase (decrease) in short-term borrowings	(60,000)	500
Borrowings from Ecova line of credit	0	3,000
Repayment of borrowings from Ecova line of credit	(4,000)	(3,000)
Redemption and maturity of long-term debt	(69)	(101)
Maturity of nonrecourse long-term debt of Spokane Energy	(3,966)	(3,622)
Issuance of common stock	638	1,149
Cash dividends paid	(19,217)	(18,384)
Increase (decrease) in client fund obligations	(1,989)	15,399
Other	0	99
Net cash used in financing activities	(88,603)	(4,960)
Net increase in cash and cash equivalents	7,598	13,733
Cash and cash equivalents at beginning of period	82,574	75,464
Cash and cash equivalents at end of period	90,172	89,197
Cash paid during the year:
Interest	8,107	7,391
Income taxes	(99)	(1,329)
Non-cash financing and investing activities:
Accounts payable for capital expenditures	5,168	4,730
Redeemable noncontrolling interests	$ 3	$ 2,870