CONDENSED CONSOLIDATED STATEMENTS OF CAPITAL STOCK AND LONG-TERM DEBT (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Common Stock, No Par Value	$ 218,100	$ 217,451
Retained Earnings	136,998	128,757
TOTAL COMMON EQUITY	355,098	346,208
TOTAL PREFERRED STOCK	2,084	2,084
SUBTOTAL LONG-TERM DEBT	276,505	277,241
Add: Premium on Issuance of Long-term Debt	7,470	7,669
Less: Unamortized Debt Expense	(4,301)	(4,411)
Less: Current Portion of Long-term Debt	(7,170)	(7,255)
TOTAL LONG-TERM DEBT	272,504	273,244
Convertible Preferred Stock $7.00 Series [Member]
TOTAL PREFERRED STOCK	1,005	1,005
Nonredeemable Preferred Stock $7.00 Series [Member]
TOTAL PREFERRED STOCK	79	79
Nonredeemable Preferred Stock $4.75 Series [Member]
TOTAL PREFERRED STOCK	1,000	1,000
First Mortgage Bonds [Member]
SUBTOTAL LONG-TERM DEBT	187,199	187,667
Amortizing Secured Notes [Member]
SUBTOTAL LONG-TERM DEBT	29,133	30,643
State Revolving Trust Notes [Member]
SUBTOTAL LONG-TERM DEBT	8,032	8,384
State Revolving Fund Bond [Member]
SUBTOTAL LONG-TERM DEBT	10	11
Construction Loans [Member]
SUBTOTAL LONG-TERM DEBT	$ 52,131	$ 50,536