Consolidated Statments of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net income	$ 45,017	$ 56,738	$ 47,254
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	63,182	63,322	60,250
Amortization of debt premium and expenses	825	797	1,081
Changes in deferred income taxes	24,393	34,125	9,800
Change in value of life insurance contracts	218	(994)	(1,878)
Stock-based compensation	2,578	2,195	1,832
(Gain) on sale of non-utility property	(315)	(51)	0
Changes in operating assets and liabilities:
Receivables	1,855	4,983	(7,201)
Unbilled revenue	559	(6,706)	(1,640)
Taxes, prepaid expenses, and other assets	(2,366)	(4,160)	1,490
Accounts payable	(819)	(1,370)	3,809
Other current liabilities	(1,106)	(5,428)	(868)
Other changes in noncurrent assets and liabilities	10,610	(15,318)	10,244
Net cash provided by operating activities	144,631	128,133	124,173
Investing activities:
Utility plant expenditures	(176,833)	(132,015)	(122,988)
Proceeds from sale of non-utility assets	319	57	0
Purchase of life insurance	(2,032)	(3,207)	(3,281)
Change in restricted cash	288	396	1,073
Net cash used in investing activities	(178,258)	(134,769)	(125,196)
Financing activities:
Short-term borrowings net of expenses of $1,197 for 2015, none for 2014 and 2013	94,303	117,300	70,615
Repayment of short-term borrowings	(141,000)	(85,000)	(113,275)
Issuance of common stock	0	0	110,688
Common stock issuance cost	0	0	(5,111)
Issuance of long-term debt, net of expenses of $707 for 2015, none for 2014 and 2013	99,343	497	48
Advances and contributions in aid of construction	16,026	12,329	10,563
Refunds of advances for construction	(6,726)	(6,641)	(6,922)
Retirement of long-term debt	(7,003)	(8,705)	(47,248)
Dividends paid	(32,066)	(31,063)	(29,619)
Net cash provided by (used in) financing activities	22,877	(1,283)	(10,261)
Change in cash and cash equivalents	(10,750)	(7,919)	(11,284)
Cash and cash equivalents at beginning of year	19,587	27,506	38,790
Cash and cash equivalents at end of year	8,837	19,587	27,506
Cash paid (received) during the year for:
Interest (net of amounts capitalized)	25,345	21,722	28,171
Income taxes	0	0	7,700
Income tax refunds	0	(6,000)	0
Supplemental disclosure of investing and financing non-cash activities:
Accrued payables for investments in utility plant	21,546	15,621	9,932
Utility plant contributed by developers	7,383	11,556	17,329
Litigation proceeds for MTBE contamination reclassified from other long-term liabilities to Capital	$ 332	$ 0	$ 7,029