ACQUISITION - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jan. 25, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Aggregate purchase price				$ 0.0	$ 304.1
Cash acquired from acquisition	$ 7.6
Inventory valuation adjustments		$ 226.6	$ 204.2	435.6	392.9
Interest expense		5.5	5.3	10.7	9.3
Loss on extinguishment of debt		0.0	0.0	0.0	1.4
Income tax expense		$ 7.2	$ 4.6	$ 13.8	10.3
Muuto Acquisition
Business Acquisition [Line Items]
Percentage of voting interests acquired	100.00%
Aggregate purchase price	$ 303.7
Acquisition costs					1.5
Interest expense					0.9
Amortization of Intangible Assets					0.1
Loss on extinguishment of debt					2.9
Income tax expense					0.9
Muuto Acquisition | Acquisition-related Costs
Business Acquisition [Line Items]
Compensation for post combination services					1.5
Muuto Acquisition | Fair Value Adjustment to Inventory
Business Acquisition [Line Items]
Inventory valuation adjustments					$ 0.9