REGULATORY MATTERS (Details) (USD $)			0 Months Ended	9 Months Ended					12 Months Ended										12 Months Ended				12 Months Ended				12 Months Ended						12 Months Ended												12 Months Ended						12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	May 22, 2011 Missouri 2012 Rate Case	Sep. 30, 2013 Missouri, Kansas and Oklahoma	Dec. 31, 2013 Cost of removal	Dec. 31, 2012 Cost of removal	Dec. 31, 2013 Unamortized gain on interest rate derivative	Dec. 31, 2012 Unamortized gain on interest rate derivative	Dec. 31, 2013 Unamortized gain on interest rate derivative Minimum	Dec. 31, 2013 Unamortized gain on interest rate derivative Maximum	Dec. 31, 2013 Deferred construction accounting costs - fuel	Dec. 31, 2012 Deferred construction accounting costs - fuel	Dec. 31, 2013 SWPA payment for Ozark Beach lost generation	Dec. 31, 2012 SWPA payment for Ozark Beach lost generation	Dec. 31, 2013 Over recovered fuel costs	Dec. 31, 2012 Over recovered fuel costs	Dec. 31, 2013 Current portion of long-term regulatory liabilities	Dec. 31, 2012 Current portion of long-term regulatory liabilities	Dec. 31, 2013 Pension and other postretirement benefits	Dec. 31, 2012 Pension and other postretirement benefits	Dec. 31, 2013 Income taxes	Dec. 31, 2012 Income taxes	Dec. 31, 2013 Storm costs	Dec. 31, 2012 Storm costs	Dec. 31, 2013 Unamortized loss on reacquired debt	Dec. 31, 2012 Unamortized loss on reacquired debt	Dec. 31, 2013 Unamortized loss on reacquired debt Minimum	Dec. 31, 2013 Unamortized loss on reacquired debt Maximum	Dec. 31, 2013 Deferred operating and maintenance expense	Dec. 31, 2012 Deferred operating and maintenance expense	Dec. 31, 2013 Unamortized loss on interest rate derivative	Dec. 31, 2012 Unamortized loss on interest rate derivative	Dec. 31, 2013 Unamortized loss on interest rate derivative Minimum	Dec. 31, 2013 Unamortized loss on interest rate derivative Maximum	Dec. 31, 2013 Deferred construction accounting costs	Dec. 31, 2012 Deferred construction accounting costs	Dec. 31, 2013 Asset retirement obligation	Dec. 31, 2012 Asset retirement obligation	Dec. 31, 2013 Customer programs	Dec. 31, 2012 Customer programs	Dec. 31, 2013 System reliability - vegetation management	Dec. 31, 2012 System reliability - vegetation management	Dec. 31, 2013 Other	Dec. 31, 2012 Other	Dec. 31, 2013 Under recovered electric fuel and purchased gas costs Missouri	Dec. 31, 2013 Ice storm and tornado cost	Dec. 31, 2013 Under recovered fuel costs	Dec. 31, 2012 Under recovered fuel costs	Dec. 31, 2013 Current portion of long-term regulatory assets	Dec. 31, 2012 Current portion of long-term regulatory assets	Dec. 31, 2013 Asbury five-year maintenance	Dec. 31, 2013 Gas Cost of removal	Dec. 31, 2012 Gas Cost of removal	Dec. 31, 2013 Electric Cost of removal	Dec. 31, 2012 Electric Cost of removal	Dec. 31, 2013 Electric Unsettled derivative losses	Dec. 31, 2012 Electric Unsettled derivative losses
Regulatory Assets and Liabilities
Deferred tornado costs recovery period			10 years
Regulatory Assets:
Regulatory assets, current	$ 7,743,000	$ 6,377,000																																													$ 1,411,000	$ 2,885,000	$ 6,332,000	$ 3,492,000
Regulatory assets, long-term	169,333,000	243,958,000																	70,035,000	136,480,000	48,033,000	48,759,000	4,911,000	4,828,000	11,078,000	12,142,000			2,095,000	2,049,000	989,000	1,147,000			16,275,000	16,717,000	4,673,000	4,430,000	4,935,000	4,356,000	7,539,000	9,002,000	833,000	669,000		3,700,000		314,000	(6,332,000)	(3,492,000)						4,269,000	6,557,000
Regulatory assets, total	177,076,000	250,335,000																																			4,700,000	4,400,000
Regulatory Asset Noncurrent, Amortization Period									1 year	28 years									5 years				5 years				1 year	28 years					1 year	28 years																	5 years
Period to recover costs in Missouri, Kansas and Oklahoma rates				12 months																																									12 months
Portion of regulatory assets expected to be recoverable in future periods																			61,200,000
Regulatory Liabilities:
Regulatory liabilities, current	5,681,000	6,303,000													2,212,000	3,214,000	3,469,000	3,089,000
Regulatory liabilities, long-term	132,012,000	131,055,000			88,469,000	83,368,000	3,371,000	3,541,000			8,011,000	8,156,000	19,405,000	22,242,000	2,371,000	2,858,000	(3,469,000)	(3,089,000)	2,177,000	2,007,000	11,677,000	11,972,000
Regulatory liabilities, total	$ 137,693,000	$ 137,358,000																																																		$ 7,200,000	$ 6,100,000	$ 81,300,000	$ 77,300,000