Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities:
Net income	$ 37,712	$ 37,656	$ 40,554
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	51,981	45,265	41,643
Amortization of debt premium and expenses	1,082	979	970
Other changes in noncurrent assets and liabilities	5,329	3,725	3,688
Change in value of life insurance contracts	1,876	(2,641)	(4,107)
Gain on sale of non-utility property	(62)	(22)	(560)
Changes in operating assets and liabilities:
Receivables	(8,213)	(860)	(9,557)
Unbilled revenue	(1,143)	(508)	(305)
Taxes, prepaid expenses, and other assets	11,823	(2,842)	(2,332)
Accounts payable	4,612	220	1,340
Other current liabilities	8,270	(598)	734
Other changes, net	(1,995)	(4,864)	356
Net adjustments	73,560	37,854	31,870
Net cash provided by operating activities	111,272	75,510	72,424
Investing activities:
Utility plant expenditures	(118,546)	(123,926)	(110,608)
Proceeds from sale of non-utility assets	64	34	810
Purchase of life insurance	(1,744)	(1,891)	(1,813)
Changes in restricted cash	(3,042)	3,169	(3,104)
Net cash provided by (used in) investing activites	(123,268)	(122,614)	(114,715)
Financing activities:
Short-term borrowings	23,390	85,750	20,000
Repayment of short-term borrowings		(74,000)	(48,000)
Issuance of common stock, net of expenses	965	912	614
Issuance of long-term debt, net of expenses	178	106,173	97,980
Advances and contributions in aid of construction	7,231	5,313	4,981
Refunds of advances for construction	(6,205)	(6,188)	(6,039)
Retirement of long-term debt	(2,963)	(13,692)	(6,772)
Dividends paid	(25,674)	(24,753)	(24,476)
Net cash (used in) provided by financing activities	(3,078)	79,515	38,288
Change in cash and cash equivalents	(15,074)	32,411	(4,003)
Cash and cash equivalents at beginning of year	42,277	9,866	13,869
Cash and cash equivalents at end of year	27,203	42,277	9,866
Cash paid (received) during the year for:
Interest (net of amounts capitalized)	26,998	24,425	20,351
Income taxes	10,535	9,815	14,003
Income tax refunds	(11,028)		(2,500)
Supplemental disclosure of non-cash activities:
Accrued payables for investments in utility plant	9,008	6,565	9,570
Utility plant contributed by developers	14,991	31,422	24,198
MTBE reclassification from other long-term liabilities to CIAC	16,735
Hawthorne capital lease	$ 9,388