INDEBTEDNESS (NARRATIVE) (DETAILS) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Feb. 11, 2016
INDEBTEDNESS [ABSTRACT]
Initiation date of current line of credit agreement			Feb. 11, 2016
Line of Credit Facility, Expiration Date			Feb. 11, 2021
Initial Borrowing Capacity			$ 900,000,000.0
Maximum borrowing capacity			$ 1,200,000,000
Line of Credit Facility, Interest Rate Description			On October 30, 2017, the Company entered into a Third Amendment to the Credit Agreement and exercised the Credit Facility's accordion feature to increase the total commitment under the Credit Facility to $1.2 billion. All other material terms of the Credit Agreement remained unchanged.Base rate loans bear interest at a rate equal to the greatest of (i) Wells Fargo's prime rate, (ii) one half of 1% in excess of the federal funds effective rate, and (iii) 1.25% in excess of the one month London Interbank Offered Rate ("LIBOR"); plus in each case a margin of 0% to 0.75% based on the Company's net leverage ratio. Eurodollar loans bear interest at LIBOR plus a margin of 1.0% to 1.75% based on the Company's net leverage ratio. Alternate currency loans bear interest at rates applicable to their respective currencies.
Line of Credit Facility, Commitment Fee Description			The Credit Facility commitment fees are payable to the lenders in an amount equal to the unused portion of the Credit Facility at a rate of 0.125% to 0.250% based on the Company's net leverage ratio.The Company is obligated to maintain a maximum net leverage ratio of 3.25 to 1.00, and a minimum interest coverage ratio of 2.50 to 1.00.
Description of line of credit agreement			The Credit Agreement provides for a secured revolving credit facility that matures on February 11, 2021 with an initial maximum aggregate commitment of $900.0 million, and an accordion feature of up to $1.2 billion in the aggregate, if certain conditions are satisfied.
Borrowings outstanding on credit facility	$ 344,000,000	$ 217,300,000
Average daily utilization under credit facility	494,700,000	$ 375,300,000
Letters of credit issued under credit facility	4,500,000
Remaining borrowing capacity under credit facility	350,000,000
Letters Of Credit Issued Outside Line Of Credit Facility	$ 700,000