WISCONSIN ECONOMIC DEVELOPMENT TAX CREDIT (Details) - Wisconsin Economic Development Tax Credit Agreement $ in Thousands	3 Months Ended		6 Months Ended	18 Months Ended
	Jun. 30, 2016 USD ($)	Mar. 31, 2015 USD ($) item	Jun. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)
Agreements
Refundable tax credits available, contingent on the Company expending $26.3 million in capital investments and establishing 758 full-time positions		$ 9,000
Capital investment expenditures over specified period, requirement to earn the refundable tax credits		$ 26,300
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				$ 3,300
Refundable tax credit received				200
Refundable tax credit receivable	$ 3,100		$ 3,100	3,100
Amortization of tax credits	152		274
Prepaid expenses and other current assets
Agreements
Refundable tax credit receivable	900		900	900
Other long-term assets
Agreements
Refundable tax credit receivable	2,200		2,200	2,200
Short-term other liabilities
Agreements
Refundable tax credit, offsetting liability	700		700	700
Other long-term liabilities
Agreements
Refundable tax credit, offsetting liability	$ 2,200		$ 2,200	$ 2,200