CONDENSED CONSOLIDATED STATEMENTS OF CAPITAL STOCK AND LONG-TERM DEBT (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Common Stock, No Par Value	$ 146,694	$ 146,185
Retained Earnings	42,651	42,560
TOTAL COMMON EQUITY	189,345	188,745
TOTAL PREFERRED STOCK	2,859	2,886
SUBTOTAL LONG-TERM DEBT	132,394	133,112
Add: Premium on Issuance of Long-term Debt	2,017	2,072
Less: Current Portion of Long-term Debt	(5,377)	(5,386)
TOTAL LONG-TERM DEBT	129,034	129,798
Amortizing Secured Note, due December 20, 2021 [Member]
SUBTOTAL LONG-TERM DEBT	1,962	2,005
Amortizing Secured Note, due May 19, 2028 [Member]
SUBTOTAL LONG-TERM DEBT	5,950	6,055
Amortizing Secured Note, due August 25, 2030 [Member]
SUBTOTAL LONG-TERM DEBT	4,597	4,667
Amortizing Secured Note, due September 19, 2031 [Member]
SUBTOTAL LONG-TERM DEBT	4,877	4,947
State Revolving Trust Note, due December 31, 2022 [Member]
SUBTOTAL LONG-TERM DEBT	465	465
State Revolving Trust Note, due May 1, 2025 [Member]
SUBTOTAL LONG-TERM DEBT	2,654	2,654
State Revolving Trust Note, due March 1, 2026 [Member]
SUBTOTAL LONG-TERM DEBT	524	541
State Revolving Trust Note, due January 25, 2027 [Member]
SUBTOTAL LONG-TERM DEBT	553	569
State Revolving Trust Note, due December 1, 2026 [Member]
SUBTOTAL LONG-TERM DEBT	742	742
State Revolving Trust Bond 4.00% to 5.00%, due August 1, 2021 [Member]
SUBTOTAL LONG-TERM DEBT	343	343
State Revolving Trust Bond 0.00%, due August 1, 2021 [Member]
SUBTOTAL LONG-TERM DEBT	275	281
State Revolving Trust Note, due July 1, 2028 [Member]
SUBTOTAL LONG-TERM DEBT	330	330
State Revolving Trust Note, due January 1, 2028 [Member]
SUBTOTAL LONG-TERM DEBT	110	110
State Revolving Trust Note, due August 1, 2031 [Member]
SUBTOTAL LONG-TERM DEBT	677	467
Amortizing Secured Note 6.59%, due April 20, 2029 [Member]
SUBTOTAL LONG-TERM DEBT	5,261	5,348
Amortizing Secured Note 7.05%, due January 20, 2030 [Member]
SUBTOTAL LONG-TERM DEBT	3,958	4,021
Amortizing Secured Note 5.69%, due January 20, 2030 [Member]
SUBTOTAL LONG-TERM DEBT	8,120	8,247
State Revolving Trust Note, due July 1, 2031 [Member]
SUBTOTAL LONG-TERM DEBT	2,515	2,515
State Revolving Trust Note, due November 30, 2030 [Member]
SUBTOTAL LONG-TERM DEBT	1,333	1,333
First Mortgage Bonds - Series X [Member]
SUBTOTAL LONG-TERM DEBT	262	268
First Mortgage Bonds - Series Y [Member]
SUBTOTAL LONG-TERM DEBT	300	300
First Mortgage Bonds - Series Z [Member]
SUBTOTAL LONG-TERM DEBT	658	671
First Mortgage Bonds - Series AA [Member]
SUBTOTAL LONG-TERM DEBT	830	830
First Mortgage Bonds - Series BB [Member]
SUBTOTAL LONG-TERM DEBT	945	965
First Mortgage Bonds - Series EE [Member]
SUBTOTAL LONG-TERM DEBT	3,882	3,968
First Mortgage Bonds - Series GG [Member]
SUBTOTAL LONG-TERM DEBT	1,152	1,171
First Mortgage Bonds - Series II [Member]
SUBTOTAL LONG-TERM DEBT	950	971
First Mortgage Bonds - Series KK [Member]
SUBTOTAL LONG-TERM DEBT	1,322	1,346
First Mortgage Bonds - Series MM [Member]
SUBTOTAL LONG-TERM DEBT	1,604	1,637
First Mortgage Bonds - Series OO [Member]
SUBTOTAL LONG-TERM DEBT	2,659	2,709
First Mortgage Bonds - Series QQ [Member]
SUBTOTAL LONG-TERM DEBT	9,915	9,915
First Mortgage Bonds - Series RR [Member]
SUBTOTAL LONG-TERM DEBT	22,500	22,500
First Mortgage Bonds - Series SS [Member]
SUBTOTAL LONG-TERM DEBT	23,000	23,000
First Mortgage Bonds - Series TT [Member]
SUBTOTAL LONG-TERM DEBT	2,809	2,860
First Mortgage Bonds - Series CC [Member]
SUBTOTAL LONG-TERM DEBT	1,145	1,145
First Mortgage Bonds - Series FF [Member]
SUBTOTAL LONG-TERM DEBT	5,335	5,335
First Mortgage Bonds - Series HH [Member]
SUBTOTAL LONG-TERM DEBT	1,475	1,475
First Mortgage Bonds - Series JJ [Member]
SUBTOTAL LONG-TERM DEBT	1,165	1,165
First Mortgage Bonds - Series LL [Member]
SUBTOTAL LONG-TERM DEBT	1,505	1,505
First Mortgage Bonds - Series NN [Member]
SUBTOTAL LONG-TERM DEBT	1,835	1,835
First Mortgage Bonds - Series PP [Member]
SUBTOTAL LONG-TERM DEBT	885	885
First Mortgage Bonds - Series UU [Member]
SUBTOTAL LONG-TERM DEBT	1,015	1,015
Convertible Preferred Stock $7.00 Series [Member]
TOTAL PREFERRED STOCK	1,429	1,457
Convertible Preferred Stock $8.00 Series [Member]
TOTAL PREFERRED STOCK	350	349
Nonredeemable Preferred Stock $7.00 Series [Member]
TOTAL PREFERRED STOCK	80	80
Nonredeemable Preferred Stock $4.75 Series [Member]
TOTAL PREFERRED STOCK	$ 1,000	$ 1,000