QUARTERLY FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Total net revenues	$ 228,251	$ 137,038	$ 181,908	$ 156,709	$ 221,280	$ 132,304	$ 165,339	$ 123,945	$ 703,906	$ 642,868	$ 583,006
Cost of revenues	114,850	84,588	104,997	103,670	118,800	88,251	93,104	89,350	408,105	389,505	372,480
Operating income	80,792	22,197	50,017	24,581	65,535	16,066	46,413	11,900	177,587	139,914	105,748
Income from continuing operations	56,025	10,609	23,675	6,756	40,710	(5,007)	25,638	(10,278)	97,065	51,063	(179,679)
Income from discontinued operations, net of tax	0	57,882	2,350	316	126	(2,926)	2,160	(996)	60,548	(1,636)	(918)
Net income	56,025	68,491	26,025	7,072	40,836	(7,933)	27,798	(11,274)	157,613	49,427	(180,597)
Net income attributable to CME Ltd.	$ 55,830	$ 68,571	$ 26,041	$ 7,250	$ 40,643	$ (7,745)	$ 27,935	$ (11,065)	$ 157,692	$ 49,768	$ (180,291)
Net income per share:
Continuing operations — basic	$ 0.15	$ 0.03	$ 0.06	$ 0.02	$ 0.14	$ (0.05)	$ 0.09	$ (0.08)	$ 0.27	$ 0.16	$ (1.28)
Continuing operations — diluted	0.15	0.03	0.06	0.01	0.11	(0.05)	0.07	(0.08)	0.25	0.12	(1.28)
Discontinued operations — basic	0.00	0.15	0.01	0.00	0.00	(0.02)	0.01	(0.01)	0.18	(0.01)	0.00
Discontinued operations — diluted	0.00	0.15	0.00	0.00	0.00	(0.02)	0.00	(0.01)	0.17	0.00	0.00
Attributable to CME Ltd. — basic	0.15	0.18	0.07	0.02	0.14	(0.07)	0.10	(0.09)	0.45	0.15	(1.28)
Attributable to CME Ltd. — diluted	$ 0.15	$ 0.18	$ 0.06	$ 0.01	$ 0.11	$ (0.07)	$ 0.07	$ (0.09)	$ 0.42	$ 0.12	$ (1.28)