LONG-TERM DEBT AND OTHER FINANCING ARRANGEMENTS Guarantee Fees (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Line of Credit Facility [Line Items]
Loss on extinguishment of debt		$ (179)	$ 0	$ (288)	$ 0
Interest on long-term debt and other financing arrangements		$ 9,374	16,012	$ 22,829	33,641
CME NV and CME BV [Member]
Line of Credit Facility [Line Items]
Outstanding Shares Pledged, Percentage		100.00%		100.00%
2019 Euro Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives		0.14%		0.14%
Debt Instrument, Guarantee Fee, Stated Percentage		2.33%		2.33%
Debt Instrument, Interest Rate, Stated Percentage		1.28%		1.28%
2021 Euro Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives	[1]	0.31%		0.31%
Debt Instrument, Guarantee Fee, Stated Percentage	[1]	2.16%		2.16%
Debt Instrument, Interest Rate, Stated Percentage		1.28%		1.28%
2023 Euro Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives	[2]	0.28%		0.28%
Debt Instrument, Guarantee Fee, Stated Percentage	[2]	2.69%		2.69%
Debt Instrument, Interest Rate, Stated Percentage		1.28%		1.28%
Guarantee Fee [Member]
Line of Credit Facility [Line Items]
Interest on long-term debt and other financing arrangements		$ 5,300	$ 11,500	$ 14,000	$ 24,500
2023 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[3]	6.34%		6.34%
2023 Revolving Credit Facility [Member] | CME NV and CME BV [Member]
Line of Credit Facility [Line Items]
Outstanding Shares Pledged, Percentage						100.00%

[1] Effective until November 1, 2019. From November 1, 2019 through maturity on November 1, 2021, the rate fixed pursuant to interest rate hedges will increase to 0.47%, with a corresponding decrease in the Guarantee Fee rate, such that the all-in borrowing rate remains 3.75% if our net leverage ratio remains unchanged.

[2] Effective until February 19, 2021. From February 19, 2021 through maturity on April 26, 2023, the rate fixed pursuant to interest rate hedges will increase to 0.97%, with a corresponding decrease in the Guarantee Fee rate, such that the all-in borrowing rate remains 4.25% if our net leverage ratio remains unchanged.

[3] Based on the three month LIBOR of 2.34% as at June 30, 2018.