Fair Value, Valuation Techniques and Related Unobservable Inputs (Detail) (Presort, Meisel, XPO and EDGAR Online acquisitions, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Customer Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Fair Value	$ 31.4
Valuation Technique	Excess earnings with and without method
Customer Relationships | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Discount rate	16.00%
Attrition rate	7.00%
Customer Relationships | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Discount rate	17.00%
Attrition rate	20.00%
Technology
Acquired Finite Lived Intangible Assets [Line Items]
Fair Value	14.5
Valuation Technique	Excess earnings relief-from-royalty method cost approach
Royalty rate (after-tax)	4.50%
Technology | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Discount rate	16.00%
Obsolescence factor	10.00%
Technology | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Discount rate	17.00%
Obsolescence factor	20.00%
Trade Name
Acquired Finite Lived Intangible Assets [Line Items]
Fair Value	3.5
Valuation Technique	Relief-from-royalty method
Trade Name | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Royalty rate (after-tax)	0.30%
Discount rate	15.50%
Trade Name | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Royalty rate (after-tax)	1.20%
Discount rate	17.00%
Noncompete Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Fair Value	2.6
Valuation Technique	Excess earnings with and without method
Noncompete Agreements | Minimum
Acquired Finite Lived Intangible Assets [Line Items]
Discount rate	16.00%
Noncompete Agreements | Maximum
Acquired Finite Lived Intangible Assets [Line Items]
Discount rate	17.00%
Contingent Consideration
Acquired Finite Lived Intangible Assets [Line Items]
Fair Value	$ 3.5
Valuation Technique	Probability weighted discounted future cash flows
Discount rate	4.50%