REVENUE - Contract Balances, Significant Changes in Customer Deposits (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Balance at beginning of period	$ 30,484
Revenue recognized that was included in the contract liability balance at the beginning of the period ended March 31, 2018	6,485
Increases due to cash received, excluding amounts recognized as revenue during the period ended March 31, 2018	10,256
Balance at end of period	34,255
Muuto Acquisition
Business Acquisition [Line Items]
Increases due to cash received, excluding amounts recognized as revenue during the period ended March 31, 2018	$ 1,500