Consolidated Statements of Cash Flow (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities:
Net income attributable to common shareholders	$ 67,941	$ 51,366
Adjustments to reconcile net income attributable to common shareholders to net cash flows from operating activities:
Depreciation and amortization	58,758	59,488
Deferred income taxes	33,216	4,495
Provision for doubtful accounts	2,202	2,233
Stock-based compensation	1,727	2,159
Gain on sale of utility system	(4,317)
Gain on sale of other assets	(259)	(2,039)
Net increase in receivables, inventory and prepayments	(12,806)	(8,394)
Net decrease in payables, accrued interest, accrued taxes and other accrued liabilities	(996)	(6,684)
Other	(9,522)	(3,233)
Net cash flows from operating activities	135,944	99,391
Cash flows from investing activities:
Property, plant and equipment additions, including allowance for funds used during construction of $3,909 and $3,002	(142,844)	(140,767)
Acquisitions of utility systems and other, net	(6,533)	(1,621)
Additions to funds restricted for construction activity	(119)	(1,020)
Release of funds previously restricted for construction activity	794	4,216
Net proceeds from the sale of utility system and other assets	11,498	3,297
Proceeds from note receivable	5,289	580
Other	(383)	(4,838)
Net cash flows used in investing activities	(132,298)	(140,153)
Cash flows from financing activities:
Customers' advances and contributions in aid of construction	2,307	4,243
Repayments of customers' advances	(1,275)	(4,818)
Net proceeds of short-term debt	29,216	23,946
Proceeds from long-term debt	22,293	101,329
Repayments of long-term debt	(23,562)	(50,897)
Change in cash overdraft position	214	(9,309)
Proceeds from issuing common stock	6,388	6,188
Proceeds from exercised stock options	5,567	1,411
Stock-based compensation windfall tax benefits		117
Repurchase of common stock	(998)	(527)
Dividends paid on common stock	(42,813)	(39,678)
Net cash flows (used in) from financing activities	(2,663)	32,005
Net increase (decrease) in cash and cash equivalents	983	(8,757)
Cash and cash equivalents at beginning of period	5,934	21,869
Cash and cash equivalents at end of period	$ 6,917	$ 13,112