Quarterly Financial Data - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended		1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended
Dec. 31, 2011	Dec. 31, 2010	May 31, 2011 Boa Vista Servicos S.A.	Apr. 30, 2010 US Consumer Information Solutions APPRO Loan Origination Software	Jun. 30, 2010 US Consumer Information Solutions APPRO Loan Origination Software	Jul. 31, 2010 US Consumer Information Solutions Direct Marketing Services Division	Sep. 30, 2010 US Consumer Information Solutions Direct Marketing Services Division
Quarterly Financial Information [Line Items]
Percentage of interest acquired in Boa Vista Servicos S.A. ("BVS")			15.00%
Proceeds received from divestitures	$ 2.5	$ 181.7		$ 72.0	$ 72.0	$ 117.0	$ 117.0

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15, 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration