DEBT (Schedule of Long Term Debt) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 999,000
Less: Deferred financing costs	(2,855)
Long-term debt, net of deferred financing costs	996,145	$ 1,022,004
Term Credit Agreement borrowings due 2024 at a variable interest rate of 2.9% at September 30, 2017
Debt Instrument [Line Items]
Total debt	$ 350,000
Effective interest rate	3.30%
Debt instrument, interest rate during period	3.30%
Term Credit Agreement borrowings due 2024 at a variable interest rate of 2.9% at September 30, 2017 | LIBOR
Debt Instrument [Line Items]
Basis points on periodic interest rate	1.625%
Senior Notes due 2022 at a fixed interest rate of 3.75%
Debt Instrument [Line Items]
Total debt	$ 325,000
Fixed interest rate	3.75%
Incremental Term Loan Agreement borrowings due 2026 at a variable interest rate of 3.1% at September 30, 2017
Debt Instrument [Line Items]
Total debt	$ 300,000
Effective interest rate	3.60%
Debt instrument, interest rate during period	2.80%
Incremental Term Loan Agreement borrowings due 2026 at a variable interest rate of 3.1% at September 30, 2017 | LIBOR
Debt Instrument [Line Items]
Basis points on periodic interest rate	1.90%
Revolving Credit Facility borrowings due 2020 at an average variable interest rate of 3.1% at March 31, 2018
Debt Instrument [Line Items]
Total debt	$ 24,000
Effective interest rate	3.10%