DEBT - SUMMARY (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt
Capital leases	$ 3.1	$ 1.3
Total Debt	429.9	373.6
Less current portion	(22.0)	(21.6)
Total Long-term Debt	407.9	352.0
5.79%, payable through 2020
Debt
Total Debt	$ 31.5	$ 38.5
Interest rate (as a percent)	5.79%	5.79%	5.79%
3.66%, payable through 2023
Debt
Total Debt	$ 68.4	$ 77.5
Interest rate (as a percent)	3.66%	3.66%	3.66%
4.16%, payable through 2027
Debt
Total Debt	$ 55.0	$ 55.0
Interest rate (as a percent)	4.16%	4.16%	4.16%
4.31%, payable through 2032
Debt
Total Debt	$ 37.5	$ 37.5
Interest rate (as a percent)	4.31%	4.31%	4.31%
4.35%, payable through 2044
Debt
Total Debt	$ 100.0	$ 100.0
Interest rate (as a percent)	4.35%	4.35%
3.92%, payable through 2045
Debt
Total Debt	$ 75.0
Interest rate (as a percent)	3.92%
5.34%, payable through 2028
Debt
Total Debt	$ 28.6	$ 30.8
Interest rate (as a percent)	5.34%	5.34%	5.34%
5.27%, payable through 2029
Debt
Total Debt	$ 30.8	$ 33.0
Interest rate (as a percent)	5.27%	5.27%	5.27%
Revolving Credit Facility
Debt
Long-term Line of Credit	$ 0.0	$ 0.0