WISCONSIN ECONOMIC DEVELOPMENT TAX CREDIT (Details) - Wisconsin Economic Development Tax Credit Agreement $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2015 USD ($) item	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Agreements
Refundable tax credits available, contingent			$ 9.0
Capital investment expenditures over specified period, requirement to earn the refundable tax credits			$ 26.3
Full-time positions that must be created over a specified time period to earn the refundable tax credits | item			758
Period over which the capital investment expenditures must be incurred and the creation of full-time positions must be completed			7 years
Refundable tax credits earned				$ 9.0
Refundable tax credit received				5.9
Refundable tax credit receivable	$ 3.1			3.1
Amortization of tax credits	0.6	$ 0.6		1.7	$ 1.8
Prepaid expenses and other current assets
Agreements
Refundable tax credit receivable	1.6			1.6
Other long-term assets
Agreements
Refundable tax credit receivable	1.5			1.5
Short-term other liabilities
Agreements
Refundable tax credit, offsetting liability	$ 0.5			$ 0.5