LONG-TERM DEBT AND OTHER FINANCING ARRANGEMENTS Credit Facility and Capital Lease Obligations(Details) $ in Thousands, Kč in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2018 CZK (Kč)	Jun. 30, 2018 CZK (Kč)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Unamortized Debt Issuance Expense				$ 6,159
Senior debt				862,287	$ 1,079,187
Credit facilities (1) – (3)	[1],[2],[3]			0	0
Capital leases				10,385	9,487
Total credit facilities and capital leases				10,385	9,487
Less: current maturities				(3,505)	(2,960)
Total non-current credit facilities and capital leases				6,880	6,527
Fair Value				$ 791,212	$ 1,016,077
2023 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4]	6.34%	6.34%	6.34%
Line of Credit Facility, Maximum Borrowing Capacity				$ 75,000
Senior Debt and Credit Facilities [Member]
Line of Credit Facility [Line Items]
Senior debt				862,287
Principal Amount of Liability Component				$ 868,446
CME NV and CME BV [Member]
Line of Credit Facility [Line Items]
Outstanding Shares Pledged, Percentage		100.00%	100.00%	100.00%
CME NV and CME BV [Member] | 2023 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Outstanding Shares Pledged, Percentage					100.00%
BMG Bank Mendes Gans [Member]
Line of Credit Facility [Line Items]
Credit facilities (1) – (3)				$ 0
Line of credit facility cash pooling arrangement deposit				17,500	$ 12,400
Ceska Sporitelna [Member]
Line of Credit Facility [Line Items]
Receivables subject to a factoring agreement, recourse or non-recourse basis		Kč 575.0	Kč 575.0	$ 25,800
Basis spread on variable rate (in percent)		0.95%
Factoring Fee, Percentage			0.19%
Global Funds IFN S.A. [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate (in percent)			6.00%
Factoring Fee, Percentage			4.00%

[1] (1) We have a cash pooling arrangement with Bank Mendes Gans (“BMG”), a subsidiary of ING Bank N.V. (“ING”), which enables us to receive credit throughout the group in respect of cash balances which our subsidiaries deposit with BMG. Cash deposited by our subsidiaries with BMG is pledged as security against the drawings of other subsidiaries up to the amount deposited.As at June 30, 2018, we had deposits of US$ 17.5 million in and no drawings on the BMG cash pool. Interest is earned on deposits at the relevant money market rate. As at December 31, 2017, we had deposits of US$ 12.4 million in and no drawings on the BMG cash pool.

[2] (2) Under a factoring framework agreement with Factoring Česka spořitelna a.s., up to CZK 575.0 million (approximately US$ 25.8 million) of receivables from certain customers in the Czech Republic may be factored on a recourse or non-recourse basis. The facility has a factoring fee of 0.19% of any factored receivable and bears interest at one-month PRIBOR plus 0.95% per annum for the period that receivables are factored and outstanding.

[3] (3) Under a factoring framework agreement with Global Funds IFN S.A., receivables from certain customers in Romania may be factored on a non-recourse basis. The facility has a factoring fee of 4.0% of any factored receivable and bears interest at 6.0% per annum from the date the receivables are factored to the due date of the factored receivable.

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