Changes in the Alliance Agreement Liability (Detail) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Accounts Payable and Accrued Liabilities [Line Items]
Beginning Balance		$ 22,584
Costs related to fulfillment of technical enablement milestones	(2,500)	(317)	(5,400)
Ending Balance		$ 22,267

Name:

aciw_CostsRelatedToFulfillmentOfTechnicalEnablementMilestones

Namespace Prefix:

aciw

Data Type:

xbrli:monetaryItemType

Balance Type:

debit

Period Type:

duration