Condensed Consolidated Financial Statements - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Goodwill [Line Items]
Gross Balance prior to the end of year			$ 828,595
Total impairment, beginning of period			(47,432)
Beginning Balance		$ 781,163
Goodwill from acquisitions	[1]	2,271
Foreign currency translation adjustments		(10,174)
Ending Balance		773,260
Americas [Member]
Goodwill [Line Items]
Gross Balance prior to the end of year			523,914
Total impairment, beginning of period			(47,432)
Beginning Balance		476,482
Goodwill from acquisitions	[1]	2,462
Foreign currency translation adjustments		(1,658)
Ending Balance		477,286
EMEA [Member]
Goodwill [Line Items]
Gross Balance prior to the end of year			240,303
Beginning Balance		240,303
Goodwill from acquisitions	[1]	(191)
Foreign currency translation adjustments		(2,292)
Ending Balance		237,820
Asia/Pacific [Member]
Goodwill [Line Items]
Gross Balance prior to the end of year			$ 64,378
Beginning Balance		64,378
Foreign currency translation adjustments		(6,224)
Ending Balance		$ 58,154

[1] Goodwill from acquisitions relates to adjustments in the goodwill recorded for the acquisition of Retail Decisions Europe Limited and Retail Decisions, Inc. (collectively "ReD") as discussed in Note 2.