SEGMENT REPORTING - Reconciliation of Company's Primary Measure of Segment Profitability (EBITA) to Income from Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
EBITA	$ 192,103	$ 178,515	$ 372,455	$ 340,297
Acquisition expenses	(2,607)	(2,986)	(5,597)	(6,282)
Integration expenses	(22,578)	(8,924)	(41,846)	(17,810)
Litigation expenses	(2,664)	173	(3,964)	(75,450)
Changes in fair value of contingent consideration		(35)	2,644	640
Restructuring and plant conversion expenses	(929)	(3,058)	(1,170)	(15,360)
Contract exit costs	(12,708)		(12,708)
Amortization expense	(50,909)	(8,921)	(69,183)	(17,718)	$ (45,498)
Income from Operations	99,708	154,764	240,631	208,317
Other Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
EBITA	14,121	13,777	29,674	23,050
Amortization expense	(1,980)	(1,800)	(3,959)	(3,611)
Reportable Segments
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
EBITA	177,982	164,738	342,781	317,247
Reportable Segments | Domestic Regulated and Compliance Services
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
EBITA	164,181	140,106	315,880	269,018
Amortization expense	(32,670)	(3,482)	(43,086)	(6,685)
Reportable Segments | International Regulated and Compliance Services
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
EBITA	13,801	24,632	26,901	48,229
Amortization expense	$ (16,259)	$ (3,639)	$ (22,138)	$ (7,422)