Weighted Average Useful Life for Each Component of Contract Acquisition Costs (Detail) (Contract Acquisition Costs)	12 Months Ended
Dec. 31, 2011 Year
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Yrs)	8.6
Payments for processing rights
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Yrs)	9.6
Conversion Costs
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Yrs)	7.4

The calculated weighted-average useful life of all finite-lived intangible assets.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16265-109275

Name:	us-gaap_FiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration