DEBT - SUMMARY (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt
Total debt	$ 647.2	$ 760.1
Less: Current portion	(65.0)	(59.2)
Total Long-term Debt	582.2	700.9
Less: Deferred loan fees	(14.7)	(15.3)
Total Long-term Debt, net of deferred loan fees	567.5	685.6
3.66% payable through 2023
Debt
Total debt	$ 18.2	22.8
Interest rate (as a percent)	3.66%
4.16% payable through 2027
Debt
Total debt	$ 31.4	34.0
Interest rate (as a percent)	4.16%
3.37 %, payable through 2027
Debt
Total debt	$ 75.0	75.0
Interest rate (as a percent)	3.37%
3.14%, payable through 2031
Debt
Total debt	$ 151.2	169.6
Interest rate (as a percent)	3.14%
4.31% payable through2032
Debt
Total debt	$ 26.7	27.9
Interest rate (as a percent)	4.31%
5.34% payable through2028
Debt
Total debt	$ 15.4	17.6
Interest rate (as a percent)	5.34%
5.27% payable through 2029
Debt
Total debt	$ 17.6	19.8
Interest rate (as a percent)	5.27%
1.22 %, payable through 2043
Debt
Total debt	$ 178.0	182.0
Interest rate (as a percent)	1.22%
1.35 %, payable through 2044
Debt
Total debt	$ 133.7	139.6
Interest rate (as a percent)	1.35%
Revolving Credit Facility
Debt
Total debt		$ 71.8