GOODWILL AND OTHER INTANGIBLE ASSETS - Additional Information (Detail) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) Segment	Sep. 30, 2015 USD ($) Segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Intangible Assets by Major Class [Line Items]
Number of geographical reportable segments | Segment					2
Number of reporting units | Segment				3
Goodwill	$ 2,447,454				$ 2,447,454		$ 2,418,832	$ 2,231,582
Aggregate amortization expense	$ 9,239		$ 8,497		$ 26,957	$ 24,214	32,692
Operating permits
Intangible Assets by Major Class [Line Items]
Write off of intangibles		$ 1,200
Customer relationships
Intangible Assets by Major Class [Line Items]
Write off of intangibles		200
Finite lived intangible assets, weighted average remaining useful life					23 years 2 months 16 days
Customer relationships | Minimum
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, useful life					10 years
Customer relationships | Maximum
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, useful life					40 years
Tradenames
Intangible Assets by Major Class [Line Items]
Write off of intangibles		$ 1,000
Finite lived intangible assets, weighted average remaining useful life					16 years 4 months 17 days
Tradenames | Minimum
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, useful life					10 years
Tradenames | Maximum
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, useful life					40 years
Covenants not-to-compete
Intangible Assets by Major Class [Line Items]
Finite lived intangible assets, weighted average remaining useful life					5 years 3 months 11 days
Covenants not-to-compete | Minimum
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, useful life					3 years
Covenants not-to-compete | Maximum
Intangible Assets by Major Class [Line Items]
Finite-lived intangible assets, useful life					14 years
Domestic Regulated and Compliance Services | Income Approach Goodwill Impairment Test
Intangible Assets by Major Class [Line Items]
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount				100.00%
Domestic Regulated Recall and Returns Management Services | Income Approach Goodwill Impairment Test
Intangible Assets by Major Class [Line Items]
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount	100.00%				100.00%
International Regulated and Compliance Services
Intangible Assets by Major Class [Line Items]
Goodwill				$ 589,300
International Regulated and Compliance Services | Income Approach Goodwill Impairment Test
Intangible Assets by Major Class [Line Items]
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount				88.00%
International
Intangible Assets by Major Class [Line Items]
Goodwill	$ 558,657				$ 558,657		$ 582,430	$ 557,772
International | Puerto Rico | Goodwill
Intangible Assets by Major Class [Line Items]
Retroactive reclassification of goodwill					$ 4,300