DEBT (Details) (USD $) In Millions, unless otherwise specified																					9 Months Ended	1 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Jan. 31, 2014 Debt Instrument Redemption 2021	Jan. 31, 2014 Debt Instrument Redemption 2022 and 2023	Jan. 31, 2014 Debt Instrument Redemption 2024 to 2027	Jan. 31, 2014 Debt Instrument Redemption 2028	Jan. 31, 2014 Debt Instrument Redemption 2029 and thereafter until 2044	Sep. 30, 2014 Term Loans Payable5.79 Percent Through2020	Dec. 31, 2013 Term Loans Payable5.79 Percent Through2020	Sep. 30, 2014 Term Loans Payable3.66 Percent Through2023	Dec. 31, 2013 Term Loans Payable3.66 Percent Through2023	Sep. 30, 2014 Term Loans Payable4.16 Percent Through2027	Dec. 31, 2013 Term Loans Payable4.16 Percent Through2027	Sep. 30, 2014 Term Loans Payable4.31 Percent Through2032	Dec. 31, 2013 Term Loans Payable4.31 Percent Through2032	Sep. 30, 2014 Term Loans Payable4.35 Percent Through2044	Sep. 30, 2014 Secured Bonds Payable5.34 Percent Through2028	Dec. 31, 2013 Secured Bonds Payable5.34 Percent Through2028	Sep. 30, 2014 Secured Bonds Payable5.27 Percent Through2029	Dec. 31, 2013 Secured Bonds Payable5.27 Percent Through2029	Sep. 30, 2014 Term Notes Payable4.35 Percent Through2044	Jan. 31, 2014 Senior Unsecured Long Term Debt
Debt
Capital leases	$ 1.7	$ 2.4
Long-term Debt, Total	377.5	286.1						42.0	45.5	77.5	77.5	55.0	55.0	37.5	37.5	100.0	30.8	33.0	33.0	35.2
Less current portion	(17.1)	(12.5)
Total long-term debt	360.4	273.6
Interest rate (as a percent)								5.79%	5.79%	3.66%	3.66%	4.16%	4.16%	4.31%	4.31%	4.35%	5.34%	5.34%	5.27%	5.27%		4.35%
Debt issued																						100
Debt instrument term																						30 years
Weighted average period																					14 years 6 months
Annual principal payments			$ 5.0	$ 7.5	$ 10.0	$ 8.0	$ 2.0