GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Beginning Balance	$ 3,591,020	$ 3,758,177
Goodwill acquired during the period	23,747	52,769
Purchase accounting adjustments	(14,502)	(161,189)
Goodwill write-offs related to disposition and amounts reclassified to assets held for sale	(8,935)	(7,486)
Changes due to foreign currency fluctuations	47,244	(51,251)
Ending Balance	3,638,574	3,591,020
Domestic and Canada RCS
Goodwill [Roll Forward]
Beginning Balance	2,811,801	2,842,711
Goodwill acquired during the period	14,434	41,517
Purchase accounting adjustments	(13,885)	(77,247)
Goodwill write-offs related to disposition and amounts reclassified to assets held for sale	0	0
Changes due to foreign currency fluctuations	12,645	4,820
Ending Balance	2,824,995	2,811,801
International Regulated and Compliance Services
Goodwill [Roll Forward]
Beginning Balance	498,421	632,491
Goodwill acquired during the period	4,698	8,381
Purchase accounting adjustments	(2,147)	(78,894)
Goodwill write-offs related to disposition and amounts reclassified to assets held for sale	(8,935)	(7,486)
Changes due to foreign currency fluctuations	34,599	(56,071)
Ending Balance	526,636	498,421
Other
Goodwill [Roll Forward]
Beginning Balance	280,798	282,975
Goodwill acquired during the period	4,615	2,871
Purchase accounting adjustments	1,530	(5,048)
Goodwill write-offs related to disposition and amounts reclassified to assets held for sale	0	0
Changes due to foreign currency fluctuations	0	0
Ending Balance	$ 286,943	$ 280,798