SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Effect of Change in Accounting Principle (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
Income Statement [Abstract]
Revenue	$ 1,772,525	$ 1,582,765	$ 1,600,842	$ 1,369,648	$ 1,713,161	$ 1,536,757	$ 1,589,637	$ 1,328,876	$ 6,325,780	$ 6,168,431	$ 6,251,000
Direct operating expenses	663,688	630,264	636,641	602,355	656,219	623,741	616,221	572,543	2,532,948	2,468,724	2,395,037
Selling, general and administrative expenses	514,269	457,757	451,490	472,987	505,131	438,796	447,509	450,786	1,896,503	1,842,222	1,726,118
Operating income	387,222	247,292	285,152	60,852	324,106	225,658	307,870	112,163	980,518	969,797	1,499,102
Interest expense, net	97,679	99,255	107,600	418,397	475,317	470,250	463,232	455,337	722,931	1,864,136	1,850,119
Loss before income taxes	224,071	89,552	80,495	(550,406)	(157,072)	(246,780)	(153,475)	(358,790)	(156,288)	(916,117)	(296,203)
Income tax benefit (expense)	837	(17,769)	(146,785)	117,366	507,549	(2,051)	(17,408)	(30,684)	(46,351)	457,406	49,631
Consolidated net income (loss)	224,908	71,783	(66,290)	(433,040)	350,477	(248,831)	(170,883)	(389,474)	(202,639)	(458,711)	(246,572)
Less amount attributable to noncontrolling interest	10,003	1,705	3,609	(16,046)	(68,265)	1,659	5,591	364	(729)	(60,651)	55,484
Net loss attributable to the Company	$ 214,905	$ 70,078	$ (69,899)	$ (416,994)	$ 418,742	$ (250,490)	$ (176,474)	$ (389,838)	(201,910)	(398,060)	(302,056)
Foreign currency translation adjustments										43,851	22,932
Other comprehensive income									(14,460)	55,598	57,272
Comprehensive loss									(216,370)	(342,462)	(244,784)
Less amount attributable to noncontrolling interest									(8,713)	13,847	(1,787)
Comprehensive loss attributable to the Company									$ (207,657)	$ (356,309)	$ (242,997)
Basic (in dollars per share)	$ 2.51	$ 0.82	$ (0.82)	$ (4.89)	$ 4.92	$ (2.94)	$ (2.08)	$ (4.60)	$ (2.36)	$ (4.68)	$ (3.57)
Diluted (in dollars per share)	$ 2.51	$ 0.82	$ (0.82)	$ (4.89)	$ 4.88	$ (2.94)	$ (2.08)	$ (4.60)	$ (2.36)	$ (4.68)	$ (3.57)
As Reported
Income Statement [Abstract]
Revenue										$ 6,170,994	$ 6,260,062
Direct operating expenses										2,461,722	2,398,776
Selling, general and administrative expenses										1,851,646	1,725,899
Operating income										969,938	1,504,644
Interest expense, net										1,865,584	1,849,982
Loss before income taxes										(917,424)	(290,524)
Income tax benefit (expense)											50,474
Consolidated net income (loss)										(460,018)	(240,050)
Less amount attributable to noncontrolling interest										(66,127)	56,312
Net loss attributable to the Company										(393,891)	(296,362)
Foreign currency translation adjustments										45,661	21,983
Other comprehensive income										57,408	56,323
Comprehensive loss										(336,483)	(240,039)
Less amount attributable to noncontrolling interest										14,092	(2,208)
Comprehensive loss attributable to the Company										$ (350,575)	$ (237,831)
Basic (in dollars per share)										$ (4.64)	$ (3.50)
Diluted (in dollars per share)										$ (4.64)	$ (3.50)
Correction
Income Statement [Abstract]
Revenue										$ (2,563)	$ (9,062)
Direct operating expenses										7,002	(3,739)
Selling, general and administrative expenses										(9,424)	219
Operating income										(141)	(5,542)
Interest expense, net										(1,448)	137
Loss before income taxes										1,307	(5,679)
Income tax benefit (expense)											(843)
Consolidated net income (loss)										1,307	(6,522)
Less amount attributable to noncontrolling interest										5,476	(828)
Net loss attributable to the Company										(4,169)	(5,694)
Foreign currency translation adjustments										(1,810)	949
Other comprehensive income										(1,810)	949
Comprehensive loss										(5,979)	(4,745)
Less amount attributable to noncontrolling interest										(245)	421
Comprehensive loss attributable to the Company										$ (5,734)	$ (5,166)
Basic (in dollars per share)										$ (0.04)	$ (0.07)
Diluted (in dollars per share)										$ (0.04)	$ (0.07)