Acquisitions - Summary of Useful Lives of Customer Relationships Based on Customer Attrition (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	10 years
Euroscan Holdings B.V. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Total intangible assets	$ 17,400
Euroscan Holdings B.V. [Member] | Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	12 years
Total intangible assets	14,400
Euroscan Holdings B.V. [Member] | Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	10 years
Total intangible assets	2,400
Euroscan Holdings B.V. [Member] | Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	10 years
Total intangible assets	600
SENS [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Total intangible assets	1,270
SENS [Member] | Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	7 years
Total intangible assets	980
SENS [Member] | Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	10 years
Total intangible assets	260
SENS [Member] | Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life (in years)	3 years
Total intangible assets	$ 30