FINANCING ARRANGEMENTS (Summary of Financing Arrangements) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 07, 2012	Jul. 30, 2012
Debt Instrument [Line Items]
Long-term obligations, at par	$ 1,645,000	$ 1,395,000
Unamortized debt issuance costs and premium, net	(11,728)	(12,457)
Long-term obligations, at carrying value	1,633,272	1,382,543
Senior Notes | Senior unsecured notes, at 5.25%, due August 1, 2020 (2020 Notes)
Debt Instrument [Line Items]
Long-term obligations, at par	$ 800,000	800,000
Interest rate	5.25%			5.25%
Senior Notes | Senior unsecured notes, at 5.125%, due June 1, 2021 (2021 Notes)
Debt Instrument [Line Items]
Long-term obligations, at par	$ 845,000	$ 595,000
Interest rate	5.125%		5.125%