ACQUISITIONS (Purchase Price Assigned to Each Major Identifiable Asset and Liability) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition
Goodwill		$ 248,748	$ 236,810	$ 199,600
Headwater Companies
Business Acquisition
Cash	$ 2,700
Receivables	29,900
Inventory	56,000
Other current assets	5,100
Total current assets	93,700
Property, plant, and equipment	9,800
Intangible assets	5,700
Goodwill	33,900
Other assets	200
Total assets	143,300
Accounts payable	19,600
Accrued liabilities and other current liabilities	11,400
Current maturities of long-term debt	31,600
Total current liabilities	62,600
Long-term debt	2,000
Other long-term liabilities	700
Total liabilities	65,300
Total	78,000
Less: Fair value of original equity interest	20,600
Total purchase price	$ 57,400