CONDENSED CONSOLIDATED STATEMENTS OF CAPITAL STOCK AND LONG-TERM DEBT (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Common Stock, No Par Value	$ 145,653	$ 143,572
Retained Earnings	42,476	38,060
TOTAL COMMON EQUITY	188,129	181,632
TOTAL PREFERRED STOCK	2,886	3,353
SUBTOTAL LONG-TERM DEBT	133,845	140,361
Add: Premium on Issuance of Long-term Debt	2,124	2,236
Less: Current Portion of Long-term Debt	(5,373)	(11,130)
TOTAL LONG-TERM DEBT	130,596	131,467
Amortizing Secured Note, due December 20, 2021
SUBTOTAL LONG-TERM DEBT	2,047	2,169
Amortizing Secured Note, due May 19, 2028
SUBTOTAL LONG-TERM DEBT	6,160	6,475
Amortizing Secured Note, due August 25, 2030
SUBTOTAL LONG-TERM DEBT	4,737	4,947
Amortizing Secured Note, due September 19, 2031
SUBTOTAL LONG-TERM DEBT	5,017	5,227
State Revolving Trust Note, due December 31, 2022
SUBTOTAL LONG-TERM DEBT	486	506
State Revolving Trust Note, due May 1, 2025
SUBTOTAL LONG-TERM DEBT	3,287	3,413
State Revolving Trust Note, due January 25, 2027
SUBTOTAL LONG-TERM DEBT	569	602
State Revolving Trust Note, due December 1, 2026
SUBTOTAL LONG-TERM DEBT	763	784
State Revolving Trust Bond 4.00% to 5.00%, due August 1, 2021
SUBTOTAL LONG-TERM DEBT	344	388
State Revolving Trust Bond 0.00%, due August 1, 2021
SUBTOTAL LONG-TERM DEBT	281	320
State Revolving Trust Note, due July 1, 2028
SUBTOTAL LONG-TERM DEBT	339	347
State Revolving Trust Note, due January 1, 2028
SUBTOTAL LONG-TERM DEBT	113	116
State Revolving Trust Note, due August 1, 2031
SUBTOTAL LONG-TERM DEBT	410	397
Amortizing Secured Note, due April 20, 2029
SUBTOTAL LONG-TERM DEBT	5,436	5,697
Amortizing Secured Note 7.05%, due January 20, 2030
SUBTOTAL LONG-TERM DEBT	4,083	4,271
Amortizing Secured Note 5.69%, due January 20, 2030
SUBTOTAL LONG-TERM DEBT	8,376	8,761
State Revolving Trust Note, due July 1, 2031
SUBTOTAL LONG-TERM DEBT	2,565	2,615
State Revolving Trust Note, due November 30, 2030
SUBTOTAL LONG-TERM DEBT	1,361	1,388
First Mortgage Bonds - Series X
SUBTOTAL LONG-TERM DEBT	268	322
First Mortgage Bonds - Series Y
SUBTOTAL LONG-TERM DEBT	300	355
First Mortgage Bonds - Series Z
SUBTOTAL LONG-TERM DEBT	671	782
First Mortgage Bonds - Series AA
SUBTOTAL LONG-TERM DEBT	830	955
First Mortgage Bonds - Series BB
SUBTOTAL LONG-TERM DEBT	965	1,085
First Mortgage Bonds - Series DD
SUBTOTAL LONG-TERM DEBT		6,000
First Mortgage Bonds - Series EE
SUBTOTAL LONG-TERM DEBT	3,968	4,386
First Mortgage Bonds - Series GG
SUBTOTAL LONG-TERM DEBT	1,171	1,262
First Mortgage Bonds - Series II
SUBTOTAL LONG-TERM DEBT	971	1,060
First Mortgage Bonds - Series KK
SUBTOTAL LONG-TERM DEBT	1,346	1,435
First Mortgage Bonds - Series MM
SUBTOTAL LONG-TERM DEBT	1,637	1,801
First Mortgage Bonds - Series OO
SUBTOTAL LONG-TERM DEBT	2,709	2,860
First Mortgage Bonds - Series QQ
SUBTOTAL LONG-TERM DEBT	9,915	9,915
First Mortgage Bonds - Series RR
SUBTOTAL LONG-TERM DEBT	22,500	22,500
First Mortgage Bonds - Series SS
SUBTOTAL LONG-TERM DEBT	23,000	23,000
First Mortgage Bonds - Series TT
SUBTOTAL LONG-TERM DEBT	2,860
First Mortgage Bonds - Series CC
SUBTOTAL LONG-TERM DEBT	1,145	1,275
First Mortgage Bonds - Series FF
SUBTOTAL LONG-TERM DEBT	5,335	5,755
First Mortgage Bonds - Series HH
SUBTOTAL LONG-TERM DEBT	1,475	1,560
First Mortgage Bonds - Series JJ
SUBTOTAL LONG-TERM DEBT	1,165	1,235
First Mortgage Bonds - Series LL
SUBTOTAL LONG-TERM DEBT	1,505	1,570
First Mortgage Bonds - Series NN
SUBTOTAL LONG-TERM DEBT	1,835	1,910
First Mortgage Bonds - Series PP
SUBTOTAL LONG-TERM DEBT	885	915
First Mortgage Bonds - Series UU
SUBTOTAL LONG-TERM DEBT	1,015
Convertible Preferred Stock $7.00 Series
TOTAL PREFERRED STOCK	1,457	1,457
Convertible Preferred Stock $8.00 Series
TOTAL PREFERRED STOCK	349	816
Nonredeemable Preferred Stock $7.00 Series
TOTAL PREFERRED STOCK	80	80
Nonredeemable Preferred Stock $4.75 Series
TOTAL PREFERRED STOCK	$ 1,000	$ 1,000