ACQUISITIONS Allocation of Total Purchase Price Paid for Acquisitions (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
	Apr. 04, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 455,197		$ 455,197
Net cash paid		$ 0	$ 236,091
Sotera
Business Acquisition [Line Items]
Cash	$ 11,583
Receivables	37,521
Prepaid expenses	1,679
Property and equipment	1,499
Other intangibles	60,590
Goodwill	164,487
Deferred tax assets	142
Other assets	1,149
Total assets acquired	278,650
Accounts payable	7,007
Accrued expenses	9,818
Accrued salaries and wages	10,784
Deferred revenue	1,505
Long-term obligations	2,097
Total liabilities assumed	31,211
Net assets acquired	247,439
Net cash paid	$ 236,100			235,856
Actual cash paid				$ 247,439