CONDENSED CONSOLIDATED STATEMENTS OF CAPITAL STOCK AND LONG-TERM DEBT (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Common Stock, No Par Value	$ 229,037	$ 221,919
Retained Earnings	156,531	145,807
TOTAL COMMON EQUITY	385,568	367,726
TOTAL PREFERRED STOCK	2,084	2,084
SUBTOTAL LONG-TERM DEBT	311,272	311,146
Add: Premium on Issuance of Long-term Debt	7,072	7,271
Less: Unamortized Debt Expense	(5,119)	(5,166)
Less: Current Portion of Long-term Debt	(7,814)	(6,731)
TOTAL LONG-TERM DEBT	305,411	306,520
First Mortgage Bonds [Member]
SUBTOTAL LONG-TERM DEBT	255,641	203,892
Amortizing Secured Notes [Member]
SUBTOTAL LONG-TERM DEBT	46,266	47,613
State Revolving Trust Notes [Member]
SUBTOTAL LONG-TERM DEBT	9,365	7,510
Construction Loans [Member]
SUBTOTAL LONG-TERM DEBT		52,131
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