Amount of additional investment made in a cost-method investment after original acquisition date.

No definition available.

Name:	aciw_CostMethodInvestmentAdditionalInvestment
Namespace Prefix:	aciw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Other Income Expense [Line Items]

+ References

No definition available.

+ Details

Name:	aciw_OtherIncomeExpenseLineItems
Namespace Prefix:	aciw_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the aggregate carrying amount of all cost-method investments held by the Entity which was not evaluated for impairment. Because the fair value of cost-method investments is not readily determinable, the evaluation of whether an investment is impaired generally consists of whether an event or change in circumstances has occurred during the reporting period that may have a significant adverse effect on the fair value of the investment (an "impairment indicator"). Impairment indicators include, but are not limited to: (1) significant deterioration in the earnings performance, credit rating, asset quality, or business prospects of the investee; (2) significant adverse change in the regulatory, economic, or technological environment of the investee; (3) significant adverse change in the general market condition of either the geographic area or the industry in which the investee operates; (4) a bona fide offer to purchase (whether solicited or unsolicited), an offer by the investee to sell, or a completed auction process for the same or similar security for an amount less than the cost of the investment; or (5) factors that raise significant concerns about the investee's ability to continue as a going concern, such as negative cash flows from operations, working capital deficiencies, or noncompliance with statutory capital requirements or debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75025870&loc=d3e40691-111596

+ Details

Name:	us-gaap_CostMethodInvestmentsAggregateCarryingAmountNotEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Original amount of cost-method investments at the acquisition date.

+ References

No definition available.

+ Details

Name:	us-gaap_CostMethodInvestmentsOriginalCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_InvestmentTypeAxis=aciw_YodleeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Other, net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income Expense [Line Items]
Realized gain on available-for-sale securities	$ 24,465
Yodlee, Inc. [Member]
Other Income Expense [Line Items]
Cost basis investment		$ 9,800
Additional investment			$ 1,000
Total investments			$ 10,800
Realized gain on available-for-sale securities	$ 24,500