ACI Worldwide (ACIW) 10-K 29 Feb 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2023	Feb. 27, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	0-25346
Entity Registrant Name	ACI WORLDWIDE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-0772104
Entity Address, Address Line One	6060 Coventry Drive
Entity Address, City or Town	Elkhorn,
Entity Address, State or Province	NE
Entity Address, Postal Zip Code	68022
City Area Code	402
Local Phone Number	390-7600
Title of 12(b) Security	Common Stock, $0.005 par value
Trading Symbol	ACIW
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction Flag	false
Entity Shell Company	false
Entity Public Float			$ 1,932,768,415
Entity Common Stock, Shares Outstanding		106,412,716
Documents Incorporated by Reference	Documents Incorporated by Reference – Portions of the registrant’s definitive Proxy Statement for the Annual Meeting of Shareholders to be held on or about June 4, 2024, are incorporated by reference in Part III of this report. This registrant’s Proxy Statement will be filed with the Securities and Exchange Commission pursuant to Regulation 14A.
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Central Index Key	0000935036

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Audit Information [Abstract]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Omaha, Nebraska

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 164,239	$ 124,981
Receivables, net of allowances of $4,295 and $3,779, respectively	452,337	403,781
Settlement assets	723,039	540,667
Prepaid expenses	31,479	28,010
Other current assets	35,551	17,366
Total current assets	1,406,645	1,114,805
Noncurrent assets
Accrued receivables, net	313,983	297,818
Property and equipment, net	37,856	52,499
Operating lease right-of-use assets	34,338	40,031
Software, net	108,418	129,109
Goodwill	1,226,026	1,226,026
Intangible assets, net	195,646	228,698
Deferred income taxes, net	58,499	53,738
Other noncurrent assets	63,328	67,171
TOTAL ASSETS	3,444,739	3,209,895
Current liabilities
Accounts payable	45,964	47,997
Settlement liabilities	721,164	539,087
Employee compensation	53,892	45,289
Current portion of long-term debt	74,405	65,521
Deferred revenue	59,580	58,303
Other current liabilities	82,244	102,645
Total current liabilities	1,037,249	858,842
Noncurrent liabilities
Deferred revenue	24,780	23,233
Long-term debt	963,599	1,024,351
Deferred income taxes, net	40,735	40,371
Operating lease liabilities	29,074	33,910
Other noncurrent liabilities	25,005	36,001
Total liabilities	2,120,442	2,016,708
Commitments and contingencies (Note 13)
Stockholders’ equity
Preferred stock; $0.01 par value; 5,000,000 shares authorized; no shares issued at December 31, 2023 and 2022	0	0
Common stock; $0.005 par value; 280,000,000 shares authorized; 140,525,055 shares issued at December 31, 2023 and 2022	702	702
Additional paid-in capital	712,994	702,458
Retained earnings	1,394,967	1,273,458
Treasury stock, at cost, 32,447,317 and 32,456,227 shares at December 31, 2023 and 2022, respectively	(674,896)	(665,771)
Accumulated other comprehensive loss	(109,470)	(117,660)
Total stockholders’ equity	1,324,297	1,193,187
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 3,444,739	$ 3,209,895

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4,295	$ 3,779
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.005	$ 0.005
Common stock, shares authorized (in shares)	280,000,000	280,000,000
Common stock, shares issued (in shares)	140,525,055	140,525,055
Treasury stock, shares (in shares)	32,447,317	32,456,227

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Total revenues		$ 1,452,579	$ 1,421,901	$ 1,370,598
Operating expenses
Cost of revenue	[1]	719,211	696,071	638,871
Research and development		140,758	146,311	144,310
Selling and marketing		132,639	134,812	126,539
General and administrative		117,190	114,194	123,801
Depreciation and amortization		122,373	126,678	127,180
Total operating expenses		1,232,171	1,218,066	1,160,701
Operating income		220,408	203,835	209,897
Other income (expense)
Interest expense		(78,486)	(53,193)	(45,060)
Interest income		14,215	12,547	11,522
Other, net		(8,510)	43,446	(1,294)
Total other income (expense)		(72,781)	2,800	(34,832)
Income before income taxes		147,627	206,635	175,065
Income tax expense		26,118	64,458	47,274
Net income		$ 121,509	$ 142,177	$ 127,791
Income per common share
Basic (in dollars per share)		$ 1.12	$ 1.25	$ 1.09
Diluted (in dollars per share)		$ 1.12	$ 1.24	$ 1.08
Weighted average common shares outstanding
Basic (in shares)		108,497	113,700	117,407
Diluted (in shares)		108,857	114,238	118,647
Software as a service and platform as a service
Revenues
Total revenues		$ 849,147	$ 802,880	$ 774,342
License
Revenues
Total revenues		321,224	348,134	319,867
Maintenance
Revenues
Total revenues		205,068	200,045	210,499
Services
Revenues
Total revenues		$ 77,140	$ 70,842	$ 65,890
[1] The cost of revenue excludes charges for depreciation but includes amortization of purchased and developed software for resale.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 121,509	$ 142,177	$ 127,791
Other comprehensive income (loss):
Foreign currency translation adjustments	8,190	(18,113)	(7,102)
Total other comprehensive income (loss)	8,190	(18,113)	(7,102)
Comprehensive income	$ 129,699	$ 124,064	$ 120,689

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2020	$ 1,206,597	$ 702	$ 682,431	$ 1,003,490	$ (387,581)	$ (92,445)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	127,791			127,791
Other comprehensive income (loss)	(7,102)					(7,102)
Stock-based compensation	27,242		27,242
Shares issued and forfeited, net, under stock plans	12,460		(21,360)		33,820
Repurchase of common stock	(107,378)				(107,378)
Repurchase of stock-based compensation awards for tax withholdings	(14,833)				(14,833)
Ending balance at Dec. 31, 2021	1,244,777	702	688,313	1,131,281	(475,972)	(99,547)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	142,177			142,177
Other comprehensive income (loss)	(18,113)					(18,113)
Stock-based compensation	29,753		29,753
Shares issued and forfeited, net, under stock plans	8,113		(15,608)		23,721
Repurchase of common stock	(206,537)				(206,537)
Repurchase of stock-based compensation awards for tax withholdings	(6,983)				(6,983)
Ending balance at Dec. 31, 2022	1,193,187	702	702,458	1,273,458	(665,771)	(117,660)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	121,509			121,509
Other comprehensive income (loss)	8,190					8,190
Stock-based compensation	24,547		24,547
Shares issued and forfeited, net, under stock plans	9,600		(14,011)		23,611
Repurchase of common stock	(27,587)				(27,587)
Repurchase of stock-based compensation awards for tax withholdings	(5,149)				(5,149)
Ending balance at Dec. 31, 2023	$ 1,324,297	$ 702	$ 712,994	$ 1,394,967	$ (674,896)	$ (109,470)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Stockholders' Equity [Abstract]
Repurchase of common stock (in shares)	939,567	8,624,238	3,000,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 121,509	$ 142,177	$ 127,791
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation	23,739	23,181	20,900
Amortization	98,634	104,147	112,493
Amortization of operating lease right-of-use assets	11,620	11,036	10,515
Amortization of deferred debt issuance costs	4,323	4,561	4,685
Deferred income taxes	(4,085)	1,603	3,733
Stock-based compensation expense	24,547	29,753	27,242
Gain on divestiture	0	(38,452)	0
Other	1,921	3,028	855
Changes in operating assets and liabilities, net of impact of divestiture:
Receivables	(62,998)	(132,194)	(43,830)
Accounts payable	(3,775)	7,730	1,408
Accrued employee compensation	8,146	(3,161)	3,674
Deferred revenue	2,705	(2,977)	(17,332)
Other current and noncurrent assets and liabilities	(57,769)	(7,051)	(31,661)
Net cash flows from operating activities	168,517	143,381	220,473
Cash flows from investing activities:
Purchases of property and equipment	(8,924)	(13,103)	(20,582)
Purchases of software and distribution rights	(28,853)	(26,790)	(24,786)
Proceeds from divestiture	0	100,139	0
Net cash flows from investing activities	(37,777)	60,246	(45,368)
Cash flows from financing activities:
Proceeds from issuance of common stock	2,819	3,581	3,440
Proceeds from exercises of stock options	6,726	4,584	8,862
Repurchase of stock-based compensation awards for tax withholdings	(5,149)	(6,983)	(14,833)
Repurchase of common stock	(27,587)	(206,537)	(107,378)
Proceeds from revolving credit facility	134,000	180,000	35,000
Repayments of revolving credit facility	(115,000)	(75,000)	(90,000)
Repayments of term portion of credit agreement	(73,031)	(85,431)	(38,950)
Payments on or proceeds from other debt, net	(16,766)	(12,123)	(15,185)
Payments for debt issuance costs	(2,160)	0	0
Net increase (decrease) in settlement assets and liabilities	(15,404)	26,849	(37,834)
Net cash flows from financing activities	(111,552)	(171,060)	(256,878)
Effect of exchange rate fluctuations on cash	4,961	(2,037)	533
Net increase (decrease) in cash and cash equivalents	24,149	30,530	(81,240)
Cash and cash equivalents, including settlement deposits, beginning of period	214,672	184,142	265,382
Cash and cash equivalents, including settlement deposits, end of period	238,821	214,672	184,142
Reconciliation of cash and cash equivalents to the Consolidated Balance Sheets
Cash and cash equivalents	164,239	124,981	122,059
Settlement deposits	74,582	89,691	62,083
Total cash and cash equivalents, including settlement deposits	238,821	214,672	184,142
Supplemental cash flow information
Income taxes paid, net	65,441	43,553	46,166
Interest paid	$ 73,543	$ 48,526	$ 40,071

Nature of Business and Summary

Nature of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Nature of Business and Summary of Significant Accounting Policies	Nature of Business and Summary of Significant Accounting Policies Nature of Business ACI Worldwide, Inc., a Delaware corporation, and its subsidiaries (collectively referred to as “ACI” or the “Company”) develop, market, install, and support a broad line of software products and services primarily focused on facilitating electronic payments. In addition to its own products, the Company distributes or acts as a sales agent for software developed by third parties. These products and services are used principally by banks and intermediaries, merchants, and billers, both in domestic and international markets. Consolidated Financial Statements The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated. Capital Stock The Company’s outstanding capital stock consists of a single class of common stock. Each share of common stock is entitled to one vote for each matter subject to a stockholder’s vote and to dividends, if and when declared by the board of directors (the “board”). Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions are affected by management’s application of accounting policies, as well as uncertainty in the current economic environment. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. The Company’s cash and cash equivalents includes holdings in checking, savings, money market, and overnight sweep accounts, all of which have daily maturities, as well as time deposits with maturities of three months or less at the date of purchase. Other Current Liabilities Other current liabilities include the following (in thousands): December 31, 2023 2022 Vendor financed licenses $ 12,702 $ 13,525 Operating lease liabilities 9,348 11,218 Accrued interest 9,172 9,067 Royalties payable 5,199 3,726 Other 45,823 65,109 Total other current liabilities $ 82,244 $ 102,645 Settlement Assets and Liabilities Individuals and businesses settle their obligations to the Company’s various Biller clients using credit or debit cards or via automated clearing house (“ACH”) payments. The Company creates a receivable for the amount due from the credit or debit card processor and an offsetting payable to the client. Upon confirmation that the funds have been received, the Company settles the obligation to the client. Due to timing, in some instances, the Company may (1) receive the funds into bank accounts controlled by and in the Company’s name that are not disbursed to its clients by the end of the day, resulting in a settlement deposit on the Company’s books and (2) disburse funds to its clients in advance of receiving funds from the credit or debit card processor, resulting in a net settlement receivable position. Off Balance Sheet Settlement Accounts The Company also enters into agreements with certain Biller clients to process payment funds on their behalf. When an ACH or automated teller machine network payment transaction is processed, a transaction is initiated to withdraw funds from the designated source account and deposit them into a settlement account, which is a trust account maintained for the benefit of the Company’s clients. A simultaneous transaction is initiated to transfer funds from the settlement account to the intended destination account. These “back to back” transactions are designed to settle at the same time, usually overnight, such that the Company receives the funds from the source at the same time as it sends the funds to their destination. However, due to the transactions being with various financial institutions there may be timing differences that result in float balances. These funds are maintained in accounts for the benefit of the client which is separate from the Company’s corporate assets. As the Company does not take ownership of the funds, these settlement accounts are not included in the Company’s balance sheet. The Company is entitled to interest earned on the fund balances. The collection of interest on these settlement accounts is considered in the Company’s determination of its fee structure for clients and represents a portion of the payment for services performed by the Company. The amount of settlement funds as of December 31, 2023 and 2022, were $273.2 million and $328.7 million, respectively. Property and Equipment Property and equipment are stated at cost. Depreciation of these assets is generally computed using the straight-line method over their estimated useful lives based on asset class. As of December 31, 2023 and 2022, net property and equipment consisted of the following (in thousands): December 31, Useful Lives 2023 2022 Computer and office equipment 3 - 5 years $ 118,805 $ 132,133 Leasehold improvements Lesser of useful life of improvement or remaining life of lease 32,660 34,159 Building and improvements 7 - 30 years 14,492 15,061 Furniture and fixtures 7 years 8,803 10,200 Land Non-depreciable 1,185 1,785 Property and equipment, gross 175,945 193,338 Less: accumulated depreciation (138,089) (140,839) Property and equipment, net $ 37,856 $ 52,499 Software Software may be for internal use or for resale. Costs related to certain software, which is for resale, are capitalized in accordance with Accounting Standards Codification (“ASC”) 985-20, Costs of Software to be Sold, Leased, or Marketed , when the resulting product reaches technological feasibility. The Company generally determines technological feasibility when it has a detailed program design that takes product function, feature and technical requirements to their most detailed, logical form and is ready for coding. The Company does not typically capitalize costs related to software for resale as technological feasibility generally coincides with general availability of the software. The Company capitalizes the costs of software developed or obtained for internal use in accordance with ASC 350-40, Internal Use Software . The Company expenses all costs incurred during the preliminary project stage of its development and capitalizes the costs incurred during the application development stage. Costs incurred relating to upgrades and enhancements to the software are capitalized if it is determined that these upgrades or enhancements add additional functionality to the software. Costs incurred during the application development stage include purchased software licenses, implementation costs, consulting costs, and payroll-related costs for projects that qualify for capitalization. All other costs, primarily related to maintenance and minor software fixes, are expensed as incurred. Amortization of software for resale is determined on a product-by-product basis and begins when the product is available for licensing to customers. The annual amortization is computed using the greater of (a) the ratio of current gross revenues to the total of current and future gross revenues expected to be derived from the software or (b) the straight-line method over the remaining estimated useful life of generally five three Business Combinations The Company applies the provisions of ASC 805, Business Combinations , in the accounting for its acquisitions. It requires the Company to recognize separately from goodwill the assets acquired and the liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred and the net of the acquisition date fair values of the assets acquired and the liabilities assumed. While the Company uses its best estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, it records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to our consolidated statements of operations. Critical estimates in valuing certain intangible assets include but are not limited to future expected cash flows from customer relationships, covenants not to compete and acquired developed technologies, brand awareness and market position, as well as assumptions about the period of time the brand will continue to be used in our product portfolio, and discount rates. Management’s estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ from estimates. Other estimates associated with the accounting for acquisitions may change as additional information becomes available regarding the assets acquired and liabilities assumed. Fair Value ASC 820, Fair Value Measurements and Disclosures , (“ASC 820”) defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. ASC 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 Inputs – Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. • Level 3 Inputs – Unobservable inputs for determining the fair values of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. The fair value of the Company’s Credit Agreement approximates the carrying value due to the floating interest rate (Level 2 of the fair value hierarchy). The Company measures the fair value of its Senior Notes based on Level 2 inputs, which include quoted market prices and interest rate spreads of similar securities. The fair value of the Company’s 5.750% Senior Notes due 2026 (“2026 Notes”) was $398.5 million and $390.0 million as of December 31, 2023 and 2022, respectively. The fair values of cash and cash equivalents approximate the carrying values due to the short period of time to maturity (Level 2 of the fair value hierarchy). Goodwill and Other Intangibles In accordance with ASC 350, Intangibles – Goodwill and Other , the Company assesses goodwill for impairment annually during the fourth quarter of its fiscal year using October 1 balances or when there is evidence that events or changes in circumstances indicate that the carrying amount of the asset may not be recovered. The Company evaluates goodwill at the reporting unit level using the discounted cash flow valuation model and allocates goodwill to these reporting units using a relative fair value approach. During this assessment, management relies on a number of factors, including operating results, business plans, and anticipated future cash flows. The Company has identified its reportable segments, Banks, Merchants, and Billers, as the reporting units. As of December 31, 2023, the Company's goodwill balance of $1.2 billion was allocated $671.7 million to Banks, $137.3 million to Merchants, and $417.0 million to Billers. The key assumptions used in the discounted cash flow valuation model include discount rates, growth rates, cash flow projections and terminal value rates. Discount rates, growth rates, and cash flow projections are the most sensitive and susceptible to change, as they require significant management judgment. Discount rates are determined by using a weighted average cost of capital (“WACC”). The WACC considers market and industry data as well as company-specific risk factors. Operational management, considering industry and company-specific historical and projected data, develops growth rates and cash flow projections for each reporting unit. Terminal value rate determination follows common methodology of capturing the present value of perpetual cash flow estimates beyond the last projected period, assuming a constant WACC and low, long-term growth rates. If, as per the quantitative test, the estimated fair value of the reporting unit is less than the carrying amount of the reporting unit, impairment is recognized for the difference, limited to the amount of goodwill recognized for the reporting unit. The calculated fair value substantially exceeded the current carrying value for all reporting units for all periods. Other intangible assets, which include customer relationships and trademarks and trade names, are amortized using the straight-line method over periods ranging from four Equity Method Investment In July 2019, the Company invested $18.3 million for a 30% non-controlling financial interest in a payment technology and services company in India. The Company accounted for this investment using the equity method in accordance with ASC 323, Investments - Equity Method and Joint Ventures . The Company records its share of earnings and losses in the investment on a one-quarter lag basis. Accordingly, the Company recorded an investment of $18.5 million and $17.9 million, which is included in other noncurrent assets in the consolidated balance sheet as of December 31, 2023 and 2022, respectively. Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset group may not be recoverable. An impairment loss is recorded if the sum of the future cash flows expected to result from the use of the asset (undiscounted and without interest charges) is less than the carrying amount of the asset. The amount of the impairment charge is measured based upon the fair value of the asset group. Treasury Stock The Company accounts for shares of its common stock that are repurchased without intent to retire as treasury stock. Such shares are recorded at cost and reflected separately on the consolidated balance sheets as a reduction of stockholders’ equity. The Company issues shares of treasury stock upon exercise of stock options, issuance of restricted share units, payment of earned performance shares, and for issuance of common stock pursuant to the Company’s employee stock purchase plan. For purposes of determining the cost of the treasury shares re-issued, the Company uses the average cost method. Stock-Based Compensation Plans In accordance with ASC 718, Compensation – Stock Compensation, ("ASC 718") the Company recognizes stock-based compensation expense for awards that are probable of vesting on a straight-line basis over the requisite service period of the award, which is generally the vesting term. Stock-based compensation expense is recorded in operating expenses depending on where the respective individual’s compensation is recorded. To determine the grant date fair value of total shareholder return awards (“TSRs”), a Monte Carlo simulation model was used. The assumptions utilized in the Monte Carlo simulation models, as well as the description of the plans the stock-based awards are granted under, are described in further detail in Note 6, Stock-Based Compensation Plans . Translation of Foreign Currencies The Company’s foreign subsidiaries typically use the local currency of the countries in which they are located as their functional currency. Their assets and liabilities are translated into U.S. dollars at the exchange rates in effect at the balance sheet date. Revenues and expenses are translated at the average exchange rates during the period. Translation gains and losses are reflected in the consolidated financial statements as a component of accumulated other comprehensive income (loss). Transaction gains and losses, including those related to intercompany accounts, that are not considered to be of a long-term investment nature are included in the determination of net income. Transaction gains and losses, including those related to intercompany accounts, that are considered to be of a long-term investment nature are reflected in the consolidated financial statements as a component of accumulated other comprehensive income (loss). Income Taxes The provision for income taxes is computed using the asset and liability method, under which deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company periodically assesses its tax exposures and establishes, or adjusts, estimated unrecognized tax benefits for probable assessments by taxing authorities, including the Internal Revenue Service, and various foreign and state authorities. Such unrecognized tax benefits represent the estimated provision for income taxes expected to ultimately be paid. Recently Issued Accounting Standards Not Yet Effective In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures , to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning after December 15, 2023 and interim periods beginning after December 15, 2024, and early application is permitted. The Company is currently assessing the impact the adoption of ASU 2023-07 will have on its segment reporting disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this update will require disclosure of more disaggregated information about a reporting entity's effective tax rate reconciliation and income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024, and early application is permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently assessing the impact the adoption of ASU 2023-09 will have on its income tax disclosures.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Revenue Recognition In accordance with ASC 606, Revenue From Contracts With Customers , revenue is recognized upon transfer of control of promised products and/or services to customers in an amount that reflects the consideration the Company expects to be entitled to in exchange for those products and services. Revenue is recognized net of any taxes collected from customers and subsequently remitted to governmental authorities. Contract Combination. The Company may execute more than one contract or agreement with a single customer at or near the same time. The separate contracts or agreements may be viewed as one combined arrangement or separate agreements for revenue recognition purposes. In order to reach appropriate conclusions regarding whether such agreements should be combined, the Company evaluates whether the agreements were negotiated as a package with a single commercial objective, whether the amount of consideration to be paid in one agreement depends on the price and/or performance of another agreement, or whether the product(s) or services promised in the agreements represent a single performance obligation. The conclusions reached can impact the allocation of the transaction price to each performance obligation and the timing of revenue recognition related to those arrangements. Software as a Service (“SaaS”) and Platform as a Service (“PaaS”) Arrangements. The Company’s SaaS-based and PaaS-based arrangements, including implementation, support and other services, represent a single promise to provide continuous access (i.e. a stand-ready performance obligation) to its software solutions and their processing capabilities in the form of a service through one of the Company’s data centers. As each day of providing access to the software solution(s) is substantially the same and the customer simultaneously receives and consumes the benefits as access is provided, the Company’s single promise under its SaaS-based and PaaS-based arrangements is comprised of a series of distinct service periods. The Company’s SaaS-based and PaaS-based arrangements may include fixed consideration, variable consideration, or a combination of the two. Fixed consideration is recognized over the term of the arrangement or longer if the fixed consideration relates to a material right. A material right would be a separate performance obligation. The Company estimates the stand-alone selling price for a material right by reference to the services expected to be provided and the corresponding expected consideration. Variable consideration in these arrangements is typically a function of transaction volume or another usage-based measure. Depending upon the structure of a particular arrangement, the Company: (1) allocates the variable amount to each distinct service period within the series and recognizes revenue as each distinct service period is performed, (2) estimates total variable consideration at contract inception (giving consideration to any constraints that may apply and updating the estimates as new information becomes available) and recognizes the total transaction price over the period to which it relates, or (3) applies the ‘right to invoice’ practical expedient and recognizes revenue based on the amount invoiced to the customer during the period. License Arrangements. The Company’s software license arrangements provide the customer with the right to use functional intellectual property (as it exists at the point in time at which the license is granted) for the duration of the contract term. Implementation, support, and other services are typically considered distinct performance obligations when sold with a software license. Payment terms for the Company’s software license arrangements generally include fixed license and capacity fees that are payable up front or over time. These arrangements may also include incremental usage-based fees that are payable when the customer exceeds its contracted license capacity limits. The Company accounts for capacity overages as a usage-based royalty that is recognized when the usage occurs. When a software license arrangement contains payment terms that are extended beyond one year, a significant financing component may exist. The significant financing component is calculated as the difference between the stated value and present value of the software license fees and is recognized as interest income over the extended payment period. The total fixed software license fee net of the significant financing component is recognized as revenue at the point in time when the software is transferred to the customer. For those software license arrangements that include customer-specific acceptance provisions, such provisions are generally presumed to be substantive and the Company does not recognize revenue until the earlier of the receipt of a written customer acceptance, objective demonstration that the delivered product meets the customer-specific acceptance criteria, or the expiration of the acceptance period. The Company recognizes revenues on such arrangements upon the earlier of receipt of written acceptance or the first production use of the software by the customer. For software license arrangements in which the Company acts as a distributor of another company’s product, and in certain circumstances, modifies or enhances the product, revenues are recorded on a gross basis. These include arrangements in which the Company takes control of the products and is responsible for providing the product or service. For software license arrangements in which the Company acts as a sales agent for another company’s product, revenues are recorded on a net basis. These include arrangements in which the Company does not take control of products and is not responsible for providing the product or service. For software license arrangements in which the Company utilizes a third-party distributor or sales agent, the Company recognizes revenue upon transfer of control of the software license(s) to the third-party distributor or sales agent. The Company’s software license arrangements typically provide the customer with a standard 90-day assurance-type warranty. These warranties do not represent an additional performance obligation as services beyond assuring that the software license complies with agreed-upon specifications are not provided. Software license arrangements typically include an initial post contract customer support (maintenance or “PCS”) term of one year with subsequent renewals for additional years within the initial license period. The Company’s promise to those customers who elect to purchase PCS represents a stand-ready performance obligation that is distinct from the license performance obligation and recognized over the PCS term. The Company also provides various professional services to customers with software licenses. These include project management, software implementation, and software modification services. Revenues from arrangements to provide professional services are generally distinct from the other promises in the contract(s) and are recognized as the related services are performed. Consideration received under these arrangements is either fixed fee or on a time-and-materials basis, which represents variable consideration that must be estimated using the most likely amount based on the range of hours expected to be incurred in providing the services. The Company estimates the stand-alone selling price (“SSP”) for maintenance and professional services based on observable stand-alone sales. The Company applies the residual approach to estimate the SSP for software licenses. Refer to Note 10, Segment Information , for further details, including disaggregation of revenue based on primary solution category and geographic location. Significant Judgments The Company applies judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information. The Company also applies judgment in determining the term of an arrangement when early termination rights are provided to the customer. The Company’s software license arrangements with its customers often include multiple promises to transfer licensed software products and services. Determining whether the products and/or services are distinct performance obligations that should be accounted for separately may require significant judgment. The Company’s SaaS and PaaS arrangements may include variable consideration in the form of usage-based fees. If the arrangement that includes variable consideration in the form of usage-based fees does not meet the allocation exception for variable consideration, the Company estimates the amount of variable consideration at the outset of the arrangement using either the expected value or most likely amount method, depending on the specifics of each arrangement. These estimates are constrained to the extent that it is probable that a significant reversal of incremental revenue will not occur and are updated each reporting period as additional information becomes available. Judgment is used in determining: (1) whether the financing component in a software license agreement is significant and, if so, (2) the discount rate used in calculating the significant financing component. The Company assesses the significance of the financing component based on the ratio of license fees paid over time to total license fees. If determined to be significant, the financing component is calculated using a rate that discounts the license fees to the cash selling price. Judgment is also used in assessing whether the extension of payment terms in a software license arrangement results in variable consideration and, if so, the amount to be included in the transaction price. The Company applies the portfolio approach to estimate the amount of variable consideration in these arrangements using the most likely amount method that is based on the Company’s historical collection experience under similar arrangements. Significant judgment is required to determine the SSP for each performance obligation, the amount allocated to each performance obligation and whether it depicts the amount that the Company expects to be entitled to in exchange for the related product and/or service. As the selling prices of the Company’s software licenses are highly variable, the Company estimates SSP of its software licenses using the residual approach when the software license is sold with other services and observable SSPs exist for the other services. The Company uses a range of amounts to estimate SSP for maintenance and services. These ranges are based on stand-alone sales and vary based on the type of service and geographic region. If the SSP of a performance obligation is not directly observable, the Company will maximize observable inputs to determine its SSP. Contract Balances Timing of revenue recognition may differ from the timing of invoicing to customers. The Company records an accrued receivable when revenue is recognized prior to invoicing and the Company’s right to consideration only requires the passage of time, or deferred revenue when revenue is recognized subsequent to invoicing. Total receivables represent amounts billed and amounts earned that are to be billed in the future (i.e., accrued receivables). Included in accrued receivables are services and SaaS and PaaS revenues earned in the current period but billed in the following period and amounts due under multi-year software license arrangements with extended payment terms for which the Company has an unconditional right to invoice and receive payment subsequent to invoicing. Total receivables, net is comprised of the following (in thousands): December 31, 2023 2022 Billed receivables $ 250,423 $ 218,611 Allowance for doubtful accounts (4,295) (3,779) Billed receivables, net 246,128 214,832 Current accrued receivables, net 206,209 188,949 Long-term accrued receivables, net 313,983 297,818 Total accrued receivables, net 520,192 486,767 Total receivables, net $ 766,320 $ 701,599 No customer accounted for more than 10% of the Company’s consolidated receivables balance as of December 31, 2023. One customer accounted for 10.1% of the Company's consolidated receivables balance as of December 31, 2022. The Company maintains an allowance for doubtful accounts for expected future credit losses that is calculated based on historical experience, current economic trends, and expectations of near term economic trends. The Company regularly monitors its credit risk exposures in consolidated receivables. The following reflects activity in the Company’s allowance for doubtful accounts receivable for the periods indicated (in thousands): Years Ended December 31, 2023 2022 2021 Balance, beginning of period $ (3,779) $ (2,861) $ (3,912) Provision (increase) decrease (526) (1,496) 1,125 Amounts written off, net of recoveries 43 389 (82) Foreign currency translation adjustments and other (33) 189 8 Balance, end of period $ (4,295) $ (3,779) $ (2,861) Provision (increases) decreases recorded in general and administrative expense during the years ended December 31, 2023, December 31, 2022, and 2021, reflect adjustments in the allowance for doubtful accounts based upon collection experience, net of collection of customer-specific receivables that were previously reserved for as doubtful of collection. Deferred revenue includes amounts due or received from customers for software licenses, maintenance, services, and/or SaaS and PaaS services in advance of recording the related revenue. Changes in deferred revenue were as follows (in thousands): Balance, December 31, 2021 $ 110,350 Deferral of revenue 125,865 Recognition of deferred revenue (128,700) Divestiture (21,581) Foreign currency translation (4,398) Balance, December 31, 2022 81,536 Deferral of revenue 119,741 Recognition of deferred revenue (117,420) Foreign currency translation 503 Balance, December 31, 2023 $ 84,360 Revenue allocated to remaining performance obligations represents contracted revenue that will be recognized in future periods, which is comprised of deferred revenue and amounts that will be invoiced and recognized as revenue in future periods. This does not include: • Revenue that will be recognized in future periods from capacity overages that are accounted for as a usage-based royalty. • SaaS and PaaS revenue from variable consideration that will be recognized in accordance with the ‘right to invoice’ practical expedient or meets the allocation objective. Revenue allocated to remaining performance obligations was $665.6 million as of December 31, 2023, of which the Company expects to recognize approximately 50% over the next 12 months and the remainder thereafter. During the year ended December 31, 2023, the revenue recognized by the Company from performance obligations satisfied in previous periods was $79.0 million. Costs to Obtain and Fulfill a Contract The Company accounts for costs to obtain and fulfill its contracts in accordance with ASC 340-40. The Company capitalizes certain of its sales commissions that meet the definition of incremental costs of obtaining a contract and for which the amortization period is greater than one year. The costs associated with those sales commissions are capitalized during the period in which the Company becomes obligated to pay the commissions and are amortized over the period in which the related products or services are transferred to the customer. As of December 31, 2023 and 2022, $3.3 million and $1.5 million of these costs are included in other current assets, respectively, and $13.9 million and $14.5 million of these costs are included in other noncurrent assets, respectively, on the consolidated balance sheets. During the years ended December 31, 2023 and 2022, the Company recognized $8.7 million and $8.3 million of sales commission expense, respectively, related to the amortization of these costs, which is included in selling and marketing expense on the consolidated statements of operations.

Divestiture

Divestiture	12 Months Ended
	Dec. 31, 2023
Discontinued Operations and Disposal Groups [Abstract]
Divestiture	Divestiture Corporate Online Banking Solutions On June 7, 2022, the Company announced a definitive agreement to divest its corporate online banking solutions related assets and liabilities to One Equity Partners ("OEP") for $100.0 million, and a net working capital adjustment. The sale included employees and customer contracts as well as technology assets and intellectual property and closed on September 1, 2022. For the year ended December 31, 2022, the Company recognized a gain of $38.5 million on the sale, which is recorded in other, net on the consolidated statements of operations. During the year ended December 31, 2023 , the Company recognized a loss for the final post-closing adjustment pursuant to the definitive agreement of $0.5 million, which is recorded in other, net on the consolidated statements of operations. The Company and OEP have also entered into a Transition Services Agreement ("TSA"), whereby the Company will continue to perform certain functions on OEP's behalf during a migration period. The TSA is meant to reimburse the Company for direct costs in order to provide such functions, which are no longer generating revenue for the Company.

Debt

Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	Debt As of December 31, 2023, the Company had $124.0 million, $519.7 million, and $400.0 million outstanding under its Revolving Credit Facility, Term Loans, and Senior Notes, respectively, with up to $373.9 million of unused borrowings under the Revolving Credit Facility portion of the Credit Agreement, as amended, and up to $2.1 million of unused borrowings under the Letter of Credit agreements. The amount of unused borrowings actually available varies in accordance with the terms of the agreement. Credit Agreement On April 5, 2019, the Company (and its wholly-owned subsidiaries, ACI Worldwide Corp. and ACI Payments, Inc. entered into the Second Amended and Restated Credit Agreement (the “Credit Agreement”), with the lenders, and Bank of America, N.A., as administrative agent for the lenders, to amend and restate the Company's existing agreement, as amended, dated February 24, 2017. The amended Credit Agreement permitted the Company to borrow up to $500.0 million in the form of an additional senior secured term loan; extended the revolver and the existing term loan maturity date from February 24, 2022, to April 5, 2024; increased the maximum consolidated senior secured net leverage ratio covenant from 3.50:1.00 to 3.75:1.00; and increased the maximum consolidated total net leverage ratio covenant from 4.25:1.00 to 5.00:1.00, with subsequent decreases occurring every three quarters thereafter for a specified period of time; among other things. On May 5, 2022, the Company and Bank of America entered into the LIBOR Transition Amendment (the "Amendment") that replaced the LIBOR reference rate with the Secured Overnight Financing Rate ("SOFR") reference rate. No other terms or conditions of the Credit Agreement were changed as a result of the Amendment. On April 28, 2023, the Company and Bank of America entered into the 2023 Extension Amendment to extend the term of the Credit Facility one year to April 5, 2025. All other terms remained the same. The Credit Agreement consists of (a) a five-year $500.0 million senior secured revolving credit facility (the “Revolving Credit Facility”), which includes sublimits for (1) the issuance of standby letters of credit and (2) swingline loans, (b) a five-year $279.0 million senior secured term loan facility (the “Initial Term Loan”) and (c) a five-year $500.0 million Delayed Draw Term Loan (together with the Initial Term Loan, the "Term Loans", and together with the Initial Term Loan and the Revolving Credit Facility, the “Credit Facility”). The Credit Agreement also allows the Company to request optional incremental term loans and increases in the revolving commitment. At the Company’s option, borrowings under the Credit Facility bear interest at an annual rate equal to either (a) a base rate determined by reference to the highest of (1) the annual interest rate publicly announced by the administrative agent as its Prime Rate, (2) the federal funds effective rate plus 1/2 of 1% or (3) SOFR rate determined by reference to the costs of funds for U.S. dollar deposits for a one-month interest period, adjusted for certain additional costs plus 1% or (b) SOFR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowings, adjusted for certain additional costs plus an applicable margin. Based on the calculation of the applicable consolidated total leverage ratio, the applicable margin for borrowings under the Credit Facility is between 0.25% to 1.25% with respect to base rate borrowings and between 1.25% and 2.25% with respect to SOFR rate borrowings. Interest is due and payable monthly. The interest rate in effect for the Credit Facility as of December 31, 2023, was 7.21%. The Company is also required to pay (a) a commitment fee related to the unutilized commitments under the Revolving Credit Facility, payable quarterly in arrears, (b) letter of credit fees on the maximum amount available to be drawn under all outstanding letters of credit in an amount equal to the applicable margin on SOFR rate borrowings under the Revolving Credit Facility on an annual basis, payable quarterly in arrears, and (c) customary fronting fees for the issuance of letters of credit fees and agency fees. The Company’s obligations under the Credit Facility and cash management arrangements entered into with lenders under the Credit Facility (or affiliates thereof) and the obligations of the subsidiary guarantors are secured by first-priority security interests in substantially all assets of the Company and any guarantor, including 100% of the capital stock of ACI Worldwide Corp. and each domestic subsidiary of the Company, each domestic subsidiary of any guarantor, and 65% of the voting capital stock of each foreign subsidiary of the Company that is directly owned by the Company or a guarantor, in each case subject to certain exclusions set forth in the credit documentation governing the Credit Facility. The collateral agreement of the Credit Agreement, as amended, released the lien on certain assets of ACI Payments, Inc., our electronic bill presentment and payment affiliate, to allow ACI Payments, Inc. to comply with certain eligible securities and unencumbered asset requirements related to money transmitter or transfer license rules and regulations. The Credit Agreement contains a number of covenants that, among other things and subject to certain exceptions, restrict the Company’s and its subsidiaries' ability to: create, incur, assume or suffer to exist any additional indebtedness; create, incur, assume or suffer to exist any liens; enter into agreements and other arrangements that include negative pledge clauses; pay dividends on capital stock or redeem, repurchase or retire capital stock or subordinated indebtedness; create restrictions on the payment of dividends or other distributions by subsidiaries; make investments, loans, advances and acquisitions; merge, consolidate or enter into any similar combination or sell assets, including equity interests of the subsidiaries; enter into sale and leaseback transactions; directly or indirectly engage in transactions with affiliates; alter in any material respect the character or conduct of the business; enter into amendments of or waivers under subordinated indebtedness, organizational documents and certain other material agreements; and hold certain assets and incur certain liabilities. On February 26, 2024, the Company entered into a Refinance Amendment (the “Amendment”) to the Second Amended and Restated Credit Agreement, dated as of April 5, 2019 (as amended, restated, supplemented or otherwise modified from time to time, including by the Amendment, the “Credit Agreement”) with ACI Worldwide Corp and ACI Payments, Inc. as co-borrowers, the lenders, and Bank of America N.A, as administrative agent and lender. The Amendment, among other things, (i) provides a senior secured term loan facility in an aggregate principal amount of $500 million, (ii) provides a senior secured revolving credit facility in an aggregate principal amount of $600 million, and (iii) extends the maturity date of the Facilities to February 26, 2029. The proceeds of the borrowings under the Amendment, together with cash on hand, were used to refinance all outstanding borrowings and replace all existing revolving commitments under the Credit Agreement immediately prior to the date of the Amendment and will be used to provide ongoing working capital and for other general corporate purposes. Letters of Credit From time to time the Company enters into standby letters of credit under the terms of the Credit Agreement. These letters of credit typically have one-year terms and may include auto-renewal terms without notice of intent to terminate the agreement. As of December 31, 2023, the Company had three letter of credit agreements outstanding for a total of $2.1 million. The letters of credit reduce the maximum available borrowings under the Revolving Credit Facility to $497.9 million. Upon expiration of the letters of credit, maximum borrowings would return to $500.0 million. Senior Notes On August 21, 2018, the Company completed a $400.0 million offering of the 2026 Notes at an issue price of 100% of the principal amount in a private placement for resale to qualified institutional buyers. The 2026 Notes bear interest at an annual rate of 5.750%, payable semi-annually in arrears on February 15 and August 15 of each year, which commenced on February 15, 2019. The 2026 Notes will mature on August 15, 2026. Maturities on debt outstanding at December 31, 2023, are as follows (in thousands): Fiscal Year Ending December 31, 2024 $ 77,900 2025 565,798 2026 400,000 2027 — 2028 — Thereafter — Total $ 1,043,698 The Revolving Credit Facility and 2026 Notes do not amortize. The Term Loans do amortize, with principal payable in consecutive quarterly installments. The Credit Agreement and 2026 Notes contain certain customary affirmative covenants and negative covenants that limit or restrict, subject to certain exceptions, the incurrence of liens, indebtedness of subsidiaries, mergers, advances, investments, acquisitions, transactions with affiliates, change in nature of business, and the sale of the assets. In addition, the Credit Agreement and 2026 Notes contain certain customary mandatory prepayment provisions. The Company is also required to maintain a consolidated leverage ratio at or below a specified amount and an interest coverage ratio at or above a specified amount. As specified in the Credit Agreement and 2026 Notes agreement, if certain events occur and continue, the Company may be required to repay all amounts outstanding under the Credit Facility and 2026 Notes. As of December 31, 2023, and at all times during the period, the Company was in compliance with its financial debt covenants. Total debt is comprised of the following (in thousands): December 31, 2023 2022 Term loans $ 519,698 $ 592,729 Revolving credit facility 124,000 105,000 5.750% Senior Notes, due August 2026 400,000 400,000 Debt issuance costs (5,694) (7,857) Total debt 1,038,004 1,089,872 Less: current portion of term loans 77,900 69,906 Less: current portion of debt issuance costs (3,495) (4,385) Total long-term debt $ 963,599 $ 1,024,351 Overdraft Facility In 2019, the Company and ACI Payments, Inc. entered in to an uncommitted overdraft facility with Bank of America, N.A. The overdraft facility bears interest at the federal funds effective rate plus 2.25% based on the Company’s average outstanding balance and the frequency in which overdrafts occur. The overdraft facility acts as a secured loan under the terms of the Credit Agreement to provide an additional funding mechanism for timing differences that can occur in the bill payment settlement process. Amounts outstanding on the overdraft facility are included in other current liabilities in the consolidated balance sheet. As of December 31, 2023, there was $75.0 million available and no amount outstanding on the overdraft facility. As of December 31, 2022, there was no amount outstanding on the overdraft facility. Other The Company finances certain multi-year license agreements for internal-use software. Upon execution, these arrangements are treated as a non-cash investing and financing activity for purposes of the consolidated statements of cash flows. During the year ended December 31, 2022, the Company financed certain multi-year license agreements for internal-use software for $10.7 million, with annual payments through April 2024. As of December 31, 2023, $3.6 million was outstanding under these and other license agreements previously entered into, all of which is included in other current liabilities in the consolidated balance sheet. As of December 31, 2022, $9.3 million was outstanding under these and other license agreements previously entered into, of which $5.8 million and $3.5 million is included in other current liabilities and other noncurrent liabilities, respectively, in the consolidated balance sheet.

Software and Other Intangible A

Software and Other Intangible Assets	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Software and Other Intangible Assets	Software and Other Intangible Assets The carrying amount and accumulated amortization of the Company's software assets subject to amortization at each balance sheet date are as follows (in thousands): December 31, 2023 December 31, 2022 Gross Carrying Accumulated Amortization Net Balance Gross Carrying Accumulated Amortization Net Balance Software for internal use $ 469,325 $ (360,907) $ 108,418 $ 454,171 $ (325,062) $ 129,109 Software for internal use amortization expense recorded during the years ended December 31, 2023, 2022, and 2021, totaled $64.8 million, $68.0 million, and $69.3 million, respectively. These software amortization expense amounts are reflected in depreciation and amortization in the consolidated statements of operations. Software for resale amortization expense recorded during the years ended December 31, 2022 and 2021, totaled $0.7 million and $6.2 million, respectively. Software for resale was fully amortized during the first quarter of 2022 and, therefore, there was no amortization expense recorded during the year ended December 31, 2023. These software amortization expense amounts are reflected in cost of revenue in the condensed consolidated statements of operations. The carrying amount and accumulated amortization of the Company’s other intangible assets subject to amortization at each balance sheet date are as follows (in thousands): December 31, 2023 December 31, 2022 Gross Carrying Accumulated Amortization Net Balance Gross Carrying Accumulated Amortization Net Balance Customer relationships $ 447,654 $ (252,828) $ 194,826 $ 444,749 $ (219,057) $ 225,692 Trademarks and trade names 21,899 (21,079) 820 21,678 (18,672) 3,006 Total other intangible assets $ 469,553 $ (273,907) $ 195,646 $ 466,427 $ (237,729) $ 228,698 Other intangible assets amortization expense recorded during the years ended December 31, 2023, 2022, and 2021, totaled $33.8 million, $35.5 million, and $37.0 million, respectively. Based on capitalized intangible assets as of December 31, 2023, estimated amortization expense amounts in future fiscal years are as follows (in thousands): Fiscal Year Ending December 31, Software Other Intangible 2024 $ 51,384 $ 29,510 2025 36,140 21,042 2026 17,316 21,042 2027 2,530 20,764 2028 1,048 18,362 Thereafter — 84,926 Total $ 108,418 $ 195,646

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans Employee Stock Purchase Plan On April 6, 2017, the board approved the 2017 Employee Stock Purchase Plan (“2017 ESPP”), which was approved by shareholders at the 2017 Annual Shareholder meeting. The 2017 ESPP provides employees with an opportunity to purchase shares of the Company’s common stock. Under the Company’s 2017 ESPP, a total of 3,000,000 shares of the Company’s common stock have been reserved for issuance to eligible employees. Participating employees are permitted to designate up to the lesser of $25,000 or 10% of their annual base compensation for the purchase of common stock under the ESPP. Purchases under the ESPP are made one calendar month after the end of each fiscal quarter. The price for shares of common stock purchased under the ESPP is 85% of the stock’s fair market value on the last business day of the three-month participation period. Additionally, the discount offered pursuant to the Company’s ESPP discussed above is 15%, which exceeds the 5% non-compensatory guideline in ASC 718 and exceeds the Company’s estimated cost of raising capital. Consequently, the entire 15% discount to employees is deemed to be compensatory for purposes of calculating expense using a fair value method. Compensation expense related to the ESPP for the years ended December 31, 2023, 2022, and 2021, was approximately $0.5 million, $0.6 million, and $0.6 million, respectively. Stock Incentive Plans – Active Plans 2020 Equity and Incentive Compensation Plan On June 9, 2020, upon recommendation of the board, stockholders approved the ACI Worldwide, Inc. 2020 Equity and Incentive Compensation Plan (the “2020 Plan”). The 2020 Plan authorizes the board to provide for equity-based compensation in the form of stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance units, dividend equivalents, and certain other awards, including those denominated or payable in, or otherwise based on, the Company’s common stock ("awards"). The purpose of the 2020 Plan is to provide incentives and rewards for service and/or performance by providing awards to non-employee directors, officers, other employees, and certain consultants and other service providers of the Company and its subsidiaries. Following the approval of the 2020 Plan, the 2016 Equity and Performance Incentive Plan (the “2016 Incentive Plan”) was terminated. Termination of the 2016 Incentive Plan did not affect any equity awards outstanding under the 2016 Incentive Plan. Subject to adjustment and share counting rules as described in the 2020 Plan, a total of 6,658,754 shares of common stock are available for awards granted under the 2020 Plan. Shares underlying certain awards under the 2020 Plan, the Company’s 2005 Equity and Performance Incentive Plan (the "2005 Incentive Plan"), and the 2016 Incentive Plan (each including as amended or amended and restated) that are cancelled or forfeited, expire, are settled for cash, or are unearned after June 9, 2020, will again be available under the 2020 Plan. The board generally will be able to amend the 2020 Plan, subject to stockholder approval in certain circumstances, as described in the 2020 Plan. 2016 Equity and Performance Incentive Plan The Company's 2016 Incentive Plan provided for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, performance awards, and other awards. The 2016 Incentive Plan was adopted by the stockholders on June 14, 2016. Following the adoption of the 2016 Incentive Plan, the 2005 Incentive Plan was terminated. Subject to adjustment in certain circumstances, the maximum number of shares of common stock that was issued or transferred in connection with awards granted under the 2016 Incentive Plan was the sum of (i) 8,000,000 shares of common stock and (ii) any shares of common stock that were represented by options previously granted under the 2005 Incentive Plan which were subsequently forfeited, expired, or cancelled without delivery of common stock or which resulted in the forfeiture or relinquishment of common stock back to the Company. 2005 Equity and Performance Incentive Plan The Company's 2005 Incentive Plan, as amended, under which shares of the Company’s common stock were reserved for issuance to eligible employees or non-employee directors of the Company. The 2005 Incentive Plan provided for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, performance awards, and other awards. The maximum number of shares of the Company’s common stock that was issued or transferred in connection with awards granted under the 2005 Incentive Plan was the sum of (i) 23,250,000 shares and (ii) any shares represented by outstanding options that had been granted under designated terminated stock option plans that were subsequently forfeited, expired, or are cancelled without delivery of the Company’s common stock. Stock Options Stock options granted pursuant to the Company's incentive plans were granted at an exercise price not less than the market value per share of the Company’s common stock on the date of grant. The term of the outstanding options may not exceed ten years nor be less than one year. Vesting of options is determined by the compensation committee of the board and the administrator of the respective plan and can vary based upon the individual award agreements. In addition, outstanding options do not have dividend equivalent rights associated with them. A summary of stock option activity is as follows: Number of Shares Weighted Average Exercise Price ($) Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value of In-the-Money Options ($) Outstanding, December 31, 2022 1,221,219 $ 19.00 Exercised (343,093) 19.60 Expired (4,614) 19.63 Outstanding, December 31, 2023 873,512 $ 18.76 1.98 $ 10,345,792 Exercisable, December 31, 2023 873,512 $ 18.76 1.98 $ 10,345,792 The Company did not grant stock options during the years ended December 31, 2023, 2022, and 2021. The total intrinsic value of stock options exercised during the years ended December 31, 2023, 2022, and 2021, was $2.1 million, $2.9 million, and $11.4 million, respectively. Long-term Incentive Program Performance Share Awards During the year ended December 31, 2017, pursuant to the Company’s 2016 Incentive Plan, the Company granted long-term incentive program performance share awards (“LTIP performance shares”). These LTIP performance shares were earned based upon the achievement, over a specified period that must not be less than one year and was typically a three-year performance period, of performance goals related to (i) the compound annual growth over the performance period in the sales for the Company as determined by the Company, and (ii) the cumulative operating income or EBITDA over the performance period as determined by the Company. Up to 200% of the LTIP performance shares could be earned upon achievement of performance goals equal to or exceeding the maximum target levels for the performance goals over the performance period. On a quarterly basis, management evaluated the probability that the threshold performance goals would be achieved, if at all, and the anticipated level of attainment to determine the amount of compensation expense to record in the consolidated financial statements. During the year ended December 31, 2021, the Company modified the performance target for the remaining outstanding long-term incentive program performance shares in consideration of the impact of the COVID-19 pandemic, resulting in additional stock-based compensation expense of approximately $0.4 million. There are no LTIP performance shares outstanding as of December 31, 2023. Performance Share Awards During the years ended December 31, 2023, 2022, and 2021, pursuant to the 2020 Plan and 2016 Incentive Plan, the Company granted performance share awards with a total shareholder return component ("TSRs"). For 2023, performance awards granted are earned, if at all, based upon achievement, over a specified period that must not be less than one year and is typically a three-year performance period, of performance goals related to (i) net revenue growth and (ii) net adjusted EBITDA margin over the performance period as determined by the Company with a total shareholder return multiplier up to plus or minus 20%. Up to 200% of the performance shares could be earned upon achievement of the performance goals, including the multiplier. For 2022 and 2021, the Company granted performance shares that are earned, if at all, based upon the Company’s total shareholder return as compared to a group of peer companies over a three-year performance period. The award payout can range from 0% to 200%. To determine the grant date fair value of the TSRs, a Monte Carlo simulation model is used. The Company recognizes compensation expense for the TSRs over the performance period based on the grant date fair value. A summary of nonvested TSRs is as follows: Number of Weighted Average Nonvested as of December 31, 2022 1,011,881 $ 39.21 Granted 233,404 26.94 Forfeited (144,474) 39.54 Change in payout rate (427,685) 30.01 Nonvested as of December 31, 2023 673,126 $ 40.73 During the year ended December 31, 2023, the TSRs granted in 2020 were earned by the employees. However, the performance goals were not met and no shares were issued. The fair value of TSRs granted during the years ended December 31, 2023, 2022, and 2021, were estimated on the date of grant using the Monte Carlo simulation model, acceptable under ASC 718, using the following weighted-average assumptions: Years Ended December 31, 2023 2022 2021 Expected life (years) 2.9 3.1 2.8 Risk-free interest rate 3.6 % 1.5 % 0.3 % Volatility 37.1 % 40.0 % 41.2 % Expected dividend yield — — — Restricted Share Units During the years ended December 31, 2023, 2022, and 2021, pursuant to the 2020 Plan and the 2016 Incentive Plan, the Company granted restricted share unit awards (“RSUs”). RSUs generally have requisite service periods of three years and may vest 100% upon the three-year anniversary or in equal increments quarterly or annually. RSUs granted to the board vest one year from grant or as of the next annual shareholders meeting, whichever is earlier. Under each arrangement, RSUs are issued without direct cost to the recipient on the vesting date. The Company estimates the fair value of the RSUs based upon the market price of the Company’s stock on the date of grant. The Company recognizes compensation expense for RSUs on a straight-line basis over the requisite service period. A summary of nonvested RSUs is as follows: Number of Weighted Average Nonvested as of December 31, 2022 1,184,024 $ 30.73 Granted 1,532,978 24.87 Vested (666,026) 28.37 Forfeited (476,093) 28.15 Nonvested as of December 31, 2023 1,574,883 $ 26.81 During the year ended December 31, 2023, a total of 666,026 RSUs vested. The Company withheld 201,634 of those shares to pay the employees’ portion of the minimum payroll withholding taxes. As of December 31, 2023, there was unrecognized compensation expense of $32.2 million related to RSUs and $7.8 million related to TSRs, which the Company expects to recognize over a weighted average period of 2.1 years and 1.7 years, respectively.

Common Stock and Treasury Stock

Common Stock and Treasury Stock	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Common Stock and Treasury Stock	Common Stock and Treasury Stock In 2005, the board approved a stock repurchase program authorizing the Company, as market and business conditions warrant, to acquire its common stock and periodically authorizes additional funds for the program. In February 2023, the board approved the repurchase of the Company's common stock of up to $200.0 million, in place of the remaining purchase amounts previously authorized. The Company repurchased 939,567 shares for $27.6 million under the program for the year ended December 31, 2023. Under the program to date, the Company has repurchased 58,921,300 shares for approximately $953.8 million. As of December 31, 2023, the maximum remaining amount authorized for purchase under the stock repurchase program was $172.4 million. Subsequent to December 31, 2023, the Company has repurchased additional shares under the repurchase program. In 2006, the Company began to issue shares of treasury stock upon exercise of stock options, payment of earned performance shares (LTIP performance shares and TSRs), vesting of RSUs, and for issuances of common stock pursuant to the Company’s ESPP. Treasury shares issued by award type are as follows: Years Ended December 31, 2023 2022 2021 Stock options 343,093 406,230 546,192 LTIP performance shares — — 10,457 TSRs — 212,210 782,588 RSUs 666,026 534,759 522,618 ESPP 140,992 145,909 120,937 Total treasury shares issued 1,150,111 1,299,108 1,982,792

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share is computed in accordance with ASC 260, Earnings per Share, based on weighted average outstanding common shares. Diluted earnings per share is computed based on basic weighted average outstanding common shares adjusted for the dilutive effect of stock options, RSUs, and certain contingently issuable shares for which performance targets have been achieved. The following table reconciles the weighted average share amounts used to compute both basic and diluted earnings per share (in thousands): Years Ended December 31, 2023 2022 2021 Weighted average shares outstanding: Basic weighted average shares outstanding 108,497 113,700 117,407 Add: Dilutive effect of stock options, RSUs, and contingently issuable shares 360 538 1,240 Diluted weighted average shares outstanding 108,857 114,238 118,647 The diluted earnings per share computation excludes 1.3 million, 1.9 million, and 1.3 million options to purchase shares, RSUs, and contingently issuable shares during the years ended December 31, 2023, 2022, and 2021, respectively, as their effect would be anti-dilutive. Common stock outstanding as of December 31, 2023 and 2022, was 108,077,738 and 108,068,828, respectively.

Other, Net

Other, Net	12 Months Ended
	Dec. 31, 2023
Other Income and Expenses [Abstract]
Other, Net	Other, Net Other, net

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Segment Information	Segment Information The Company reports financial performance based on its operating segments, Banks, Merchants, and Billers, and analyzes Segment Adjusted EBITDA as a measure of segment profitability. The Company’s Chief Executive Officer is also the chief operating decision maker ("CODM"). The CODM, together with other senior management personnel, focus their review on consolidated financial information and the allocation of resources based on operating results, including revenues and Segment Adjusted EBITDA, for each segment, separate from corporate operations. No operating segments have been aggregated to form the reportable segments. Banks. ACI provides payment solutions to large and mid-size banks globally for retail banking, real time, digital, and other payment services. These solutions transform banks’ complex payment environments to speed time to market, reduce costs, and deliver a consistent experience to customers across channels while enabling them to prevent and rapidly react to fraudulent activity. In addition, they enable banks to meet the requirements of different real-time payments schemes and to quickly create differentiated products to meet consumer, business, and merchant demands. Merchants. ACI’s support of merchants globally includes Tier 1 and Tier 2 merchants, online-only merchants and the payment service providers, independent selling organizations, value-added resellers, and acquirers who service them. These customers operate in a variety of verticals, including general merchandise, grocery, hospitality, dining, transportation, and others. The Company's solutions provide merchants with a secure, omni-channel payments platform that gives them independence from third-party payment providers. They also offer secure solutions to online-only merchants that provide consumers with a convenient and seamless way to shop. Billers. Within the billers segment, ACI provides electronic bill presentment and payment (“EBPP”) services to companies operating in the consumer finance, insurance, healthcare, higher education, utility, government, and mortgage categories. The solutions enable these customers to support a wide range of payment options and provide a convenient consumer payments experience that drives consumer loyalty and increases revenue. Revenue is attributed to the reportable segments based upon customer. Expenses are attributed to the reportable segments in one of three methods: (1) direct costs of the segment, (2) labor costs that can be attributed based upon time tracking for individual projects, or (3) costs that are allocated. Allocated costs are generally marketing and sales related activities. Segment Adjusted EBITDA is the measure reported to the CODM for purposes of making decisions on allocating resources and assessing the performance of the Company’s segments, and, therefore, Segment Adjusted EBITDA is presented in conformity with ASC 280, Segment Reporting . Segment Adjusted EBITDA is defined as earnings (loss) from operations before interest, income tax expense (benefit), depreciation and amortization (“EBITDA”) adjusted to exclude net other income (expense). Corporate and unallocated expenses includes global facilities and information technology costs and long-term product roadmap expenses in addition to corporate overhead costs that are not allocated to reportable segments. The overhead costs relate to human resources, finance, legal, accounting, and merger and acquisition activity. These costs along with depreciation and amortization and stock-based compensation are not considered when management evaluates segment performance. The following is selected financial data for the Company’s reportable segments for the periods indicated (in thousands): Years Ended December 31, 2023 2022 2021 Revenues Banks $ 616,051 $ 638,585 $ 625,125 Merchants 150,616 153,905 152,988 Billers 685,912 629,411 592,485 Total revenue $ 1,452,579 $ 1,421,901 $ 1,370,598 Segment Adjusted EBITDA Banks $ 355,489 $ 371,017 $ 372,949 Merchants 44,345 49,029 54,266 Billers 142,343 107,371 129,048 Depreciation and amortization (122,373) (127,328) (133,393) Stock-based compensation expense (24,547) (29,753) (27,242) Corporate and unallocated expenses (174,849) (166,501) (185,731) Interest, net (64,271) (40,646) (33,538) Other, net (8,510) 43,446 (1,294) Income before income taxes $ 147,627 $ 206,635 $ 175,065 Assets are not allocated to segments, and the Company’s CODM does not evaluate operating segments using discrete asset information. The following is revenue by primary solution category for the Company’s reportable segments for the periods indicated (in thousands): Year Ended December 31, 2023 Banks Merchants Billers Total Primary Solution Categories Bill Payments $ — $ — $ 685,912 $ 685,912 Digital Business Banking 2,792 — — 2,792 Merchant Payments — 150,616 — 150,616 Fraud Management 63,503 — — 63,503 Real-Time Payments 128,957 — — 128,957 Issuing and Acquiring 420,799 — — 420,799 Total $ 616,051 $ 150,616 $ 685,912 $ 1,452,579 Year Ended December 31, 2022 Banks Merchants Billers Total Primary Solution Categories Bill Payments $ — $ — $ 629,411 $ 629,411 Digital Business Banking 35,504 — — 35,504 Merchant Payments — 153,905 — 153,905 Fraud Management 47,421 — — 47,421 Real-Time Payments 104,777 — — 104,777 Issuing and Acquiring 450,883 — — 450,883 Total $ 638,585 $ 153,905 $ 629,411 $ 1,421,901 Year Ended December 31, 2021 Banks Merchants Billers Total Primary Solution Categories Bill Payments $ — $ — $ 592,485 $ 592,485 Digital Business Banking 60,398 — — 60,398 Merchant Payments — 152,988 — 152,988 Fraud Management 43,704 — — 43,704 Real-Time Payments 77,922 — — 77,922 Issuing and Acquiring 443,101 — — 443,101 Total $ 625,125 $ 152,988 $ 592,485 $ 1,370,598 As discussed in Note 3, Divestiture, in 2022 the Company divested its corporate online banking solution assets, which were included in the Digital Business Banking solution category. The following is revenue by the Company's reportable segments for the periods indicated (in thousands): Year Ended December 31, 2023 2022 2021 Banks Software as a service and platform as a service $ 39,803 $ 48,932 $ 57,339 License 311,549 336,028 310,758 Maintenance 189,650 184,017 193,332 Services 75,049 69,608 63,696 Total $ 616,051 $ 638,585 $ 625,125 Merchants Software as a service and platform as a service $ 123,528 $ 124,631 $ 124,933 License 9,675 12,106 9,015 Maintenance 15,322 15,934 16,846 Services 2,091 1,234 2,194 Total $ 150,616 $ 153,905 $ 152,988 Billers Software as a service and platform as a service $ 685,816 $ 629,317 $ 592,070 License — — 94 Maintenance 96 94 321 Services — — — Total $ 685,912 $ 629,411 $ 592,485 The following is the Company's revenue by geographic location for the periods indicated (in thousands): Year Ended December 31, 2023 2022 2021 Revenue United States $ 887,168 $ 851,712 $ 869,081 Other 565,411 570,189 501,517 Total $ 1,452,579 $ 1,421,901 $ 1,370,598 The following is the Company’s long-lived assets by geographic location for the periods indicated (in thousands): December 31, 2023 2022 Long-lived Assets United States $ 1,216,158 $ 1,286,505 Other 763,437 754,847 Total $ 1,979,595 $ 2,041,352 No single customer accounted for more than 10% of the Company’s consolidated revenues during the years ended December 31, 2023, 2022, and 2021. No other country outside the United States accounted for more than 10% of the Company’s consolidated revenues during the years ended December 31, 2023, 2022, and 2021.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For financial reporting purposes, income (loss) before income taxes includes the following components (in thousands): Years Ended December 31, 2023 2022 2021 United States $ (8,342) $ (11,751) $ 69,817 Foreign 155,969 218,386 105,248 Total $ 147,627 $ 206,635 $ 175,065 The expense (benefit) for income taxes consists of the following (in thousands): Years Ended December 31, 2023 2022 2021 Federal Current $ (3,490) $ 7,064 $ 3,994 Deferred (6,306) (353) 6,067 Total (9,796) 6,711 10,061 State Current (2,327) 7,993 7,592 Deferred 797 (3,500) (1,498) Total (1,530) 4,493 6,094 Foreign Current 36,020 47,798 31,955 Deferred 1,424 5,456 (836) Total 37,444 53,254 31,119 Total $ 26,118 $ 64,458 $ 47,274 Differences between the income tax expense computed at the statutory federal income tax rate and per the consolidated statements of operations are summarized as follows (in thousands): Years Ended December 31, 2023 2022 2021 Tax expense at federal rate of 21% $ 31,002 $ 43,393 $ 36,764 State income taxes, net of federal benefit 1,744 2,351 4,816 Change in valuation allowance 1,588 71 1,228 Foreign tax rate differential (7,658) (12,949) (5,376) Unrecognized tax benefit increase (decrease) (5,726) 2,039 858 Tax effect of foreign operations 10,350 15,336 16,151 Tax benefit of research & development (5,104) (3,365) (4,123) Performance-based compensation 3,004 2,266 (1,887) Tax effect of divestiture (2,900) 14,522 — Other (182) 794 (1,157) Income tax provision $ 26,118 $ 64,458 $ 47,274 The countries having the greatest impact on the tax rate adjustment line shown in the above table as “Foreign tax rate differential” for the three years reported are Ireland, Singapore, and the United Kingdom. The deferred tax assets and liabilities result from differences in the timing of the recognition of certain income and expense items for tax and financial accounting purposes. The sources of these differences at each balance sheet date are as follows (in thousands): December 31, 2023 2022 Deferred income tax assets: Net operating loss carryforwards $ 15,409 $ 16,763 Tax credits 23,197 18,497 Compensation 15,478 15,272 Deferred revenue 9,873 10,168 Operating lease 8,297 10,202 Capitalized research and development 16,903 23,891 Deferred interest 17,822 6,829 Other 951 2,704 Gross deferred income tax assets 107,930 104,326 Less: valuation allowance (12,963) (11,384) Net deferred income tax assets $ 94,967 $ 92,942 Deferred income tax liabilities: Depreciation and amortization $ (31,741) $ (33,692) Operating lease right-of-use asset (7,303) (8,885) Unbilled revenue (5,407) (9,566) Withholding tax liability (32,752) (27,432) Total deferred income tax liabilities (77,203) (79,575) Net deferred income taxes $ 17,764 $ 13,367 Deferred income taxes / liabilities included in the balance sheet are: Deferred income tax asset – noncurrent $ 58,499 $ 53,738 Deferred income tax liability – noncurrent (40,735) (40,371) Net deferred income taxes $ 17,764 $ 13,367 The deferred tax asset and liabilities disclosure above reflects a $6.8 million deferred interest reclass for the year ended December 31, 2022. Prior year reported $6.8 million related to deferred interest as Other within the deferred tax asset section. The amount is now reported separately within the deferred tax asset section. In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. The Company considers projected future taxable income, carryback opportunities, and tax planning strategies in making this assessment. Based upon the level of historical taxable income and projections for future taxable income over the periods which the deferred tax assets are deductible, the Company believes it is more likely than not that it will realize the benefits of these deductible differences, net of the valuation allowances recorded. At December 31, 2023, the Company had domestic federal tax net operating losses (“NOLs”) of $47.9 million, of which $2.9 million may be utilized over an indefinite life, with the remainder beginning to expire in 2024. The Company had deferred tax assets equal to $0.9 million related to domestic state tax NOLs which will begin to expire in 2024. The Company did not have any valuation allowance against the federal tax NOLs but had provided a $0.5 million valuation allowance against the deferred tax asset associated with the state NOLs. The Company had foreign tax NOLs of $16.7 million, of which $16.5 million may be utilized over an indefinite life, with the remainder expiring over the next five years. The Company did not have any valuation allowance against the deferred tax asset associated with the foreign NOLs. The Company had U.S. foreign tax credit carryforwards at December 31, 2023, of $2.2 million, for which a $2.2 million valuation allowance had been provided. The U.S. foreign tax credits will begin to expire in 2028. The Company had foreign tax credit carryforwards in other foreign jurisdictions at December 31, 2023, of $3.3 million, of which $1.0 million may be utilized over an indefinite life, with the remainder expiring over the next seven years. The Company had provided a $1.0 million valuation allowance against the tax benefit associated with these foreign credits. The Company also had domestic federal general business tax credit carryforwards at December 31, 2023, of $27.4 million, which will expire in 2033 and state general business tax credit carryforwards of $0.6 million, which will begin to expire in 2024. The Company did not provide deferred taxes on $41.5 million of unremitted earnings of its Indian subsidiaries that are considered permanently reinvested. The company did not estimate the deferred tax liability on these earnings as such estimation is not practicable to determine or is immaterial to the financial statements. As of December 31, 2023, deferred taxes for non-United States withholding and other taxes were provided on $23.4 million of unremitted earnings of non-United States subsidiaries that may be remitted to the United States. As of December 31, 2023 and 2022, the Company recorded a deferred tax liability of $0.6 million and $1.3 million, respectively, related to these non-United States earnings that may be remitted. The unrecognized tax benefit at December 31, 2023 and 2022, was $20.9 million and $26.4 million, respectively, of which $10.5 million and $19.9 million, respectively, are included in other noncurrent liabilities in the consolidated balance sheets. Of the total unrecognized tax benefit amounts at December 31, 2023 and 2022, $20.1 million and $25.0 million, respectively, represent the net unrecognized tax benefits that, if recognized, would favorably impact the effective income tax rate in the respective years. A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31 is as follows (in thousands): 2023 2022 2021 Balance of unrecognized tax benefits at beginning of year $ 26,408 $ 24,510 $ 24,310 Increases for tax positions of prior years 1,568 2,349 1,533 Decreases for tax positions of prior years (6,560) (3,659) (65) Increases for tax positions established for the current period 3,941 9,320 2,272 Decreases for settlements with taxing authorities (532) (63) (620) Reductions resulting from lapse of applicable statute of limitation (4,005) (5,833) (2,876) Adjustment resulting from foreign currency translation 69 (216) (44) Balance of unrecognized tax benefits at end of year $ 20,889 $ 26,408 $ 24,510 On July 21, 2023, the Internal Revenue Service (“IRS”) issued Notice 2023-55 providing guidance to taxpayers in determining whether a foreign tax is eligible for a U.S. foreign tax credit for tax years 2022 and 2023 effectively delaying the application of an unfavorable foreign tax credit regulation until 2024. As a result of this guidance, the Company recorded a tax benefit of $6.0 million in the fiscal third quarter of 2023. The Company files income tax returns in the U.S. federal jurisdiction, various state and local jurisdictions, and many foreign jurisdictions. The United States, Ireland, and the United Kingdom are the main taxing jurisdictions in which the Company operates. The years open for audit vary depending on the tax jurisdiction. In the United States, the Company’s federal tax return for years following 2019 are open for audit. In the foreign jurisdictions, the tax returns open for audit generally vary by jurisdiction between 2006 and 2022. The Company has been notified by the U.S. Internal Revenue Service that their 2021 federal tax return has been selected to be examined. The Company’s Indian income tax returns covering fiscal years ended March 31, 2005, 2014, 2016, 2018, and 2020 are under audit by the Indian tax authority. Other foreign subsidiaries could face challenges from various foreign tax authorities. It is not certain that the local authorities will accept the Company’s tax positions. The Company believes its tax positions comply with applicable tax law and intends to vigorously defend its positions. However, differing positions on certain issues could be upheld by tax authorities, which could adversely affect the Company’s financial condition and results of operations. The Company believes it is reasonably possible that the total amount of unrecognized tax benefits will decrease within the next 12 months by approximately $2.2 million due to the settlement of various audits and the expiration of statutes of limitations. The Company accrues interest related to uncertain tax positions in interest expense or interest income and recognizes penalties related to uncertain tax positions in other income or other expense. As of December 31, 2023 and 2022, $0.5 million and $0.6 million, respectively, is accrued for the payment of interest and penalties related to income tax liabilities. The aggregate amount of interest and penalties expense (benefit) recorded in the statements of operations for the years ended December 31, 2023, 2022, and 2021, was $(0.1) million, $(0.5) million, and $(0.1) million, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	Leases The Company has operating leases primarily for corporate offices and data centers. Excluding office leases, leases with an initial term of 12-months or less that do not include an option to purchase the underlying asset are not recorded on the consolidated balance sheet and are expensed on a straight-line basis over the lease term. The Company’s leases typically include certain renewal options to extend the leases for up to 25 years, some of which include options to terminate the leases within one year. The exercise of lease renewal options is at the Company’s sole discretion. The Company combines lease and non-lease components of its leases and currently has no leases with options to purchase the leased property. Payments of maintenance and property tax costs paid by the Company are accounted for as variable lease cost, which are expensed as incurred. The components of lease cost are as follows (in thousands): Years Ended December 31, 2023 2022 2021 Operating lease cost $ 13,074 $ 12,506 $ 12,369 Variable lease cost 2,663 2,771 3,140 Total lease cost $ 15,737 $ 15,277 $ 15,509 Supplemental cash flow information related to leases is as follows (in thousands): Years Ended December 31, 2023 2022 2021 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 14,039 $ 14,020 $ 19,623 Right-of-use assets obtained in exchange for new lease obligations: Operating leases $ 6,359 $ 7,693 $ 20,944 Supplemental balance sheet information related to leases is as follows (in thousands, except lease term and discount rate): December 31, 2023 2022 Assets: Operating lease right-of-use assets $ 34,338 $ 40,031 Liabilities: Other current liabilities $ 9,348 $ 11,218 Operating lease liabilities 29,074 33,910 Total operating lease liabilities $ 38,422 $ 45,128 Weighted average remaining operating lease term (years) 5.31 5.53 Weighted average operating lease discount rate 3.47 % 3.21 % The Company uses its incremental borrowing rate as the discount rate. As the Company enters into operating leases in multiple jurisdictions and denominated in currencies other than the U.S. dollar, judgment is used to determine the Company’s incremental borrowing rate including (1) conversion of its subordinated borrowing rate (using published yield curves) to an unsubordinated and collateralized rate, (2) adjusting the rate to align with the term of each lease, and (3) adjusting the rate to incorporate the effects of the currency in which the lease is denominated. Maturities on lease liabilities as of December 31, 2023, are as follows (in thousands): Fiscal Year Ending December 31, 2024 $ 10,465 2025 8,162 2026 6,290 2027 5,580 2028 4,801 Thereafter 6,363 Total lease payments 41,661 Less: imputed interest 3,239 Total lease liability $ 38,422

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies In accordance with ASC 460, Guarantees , the Company recognizes the fair value for guarantee and indemnification arrangements it issues or modifies if these arrangements are within the scope of the interpretation. In addition, the Company must continue to monitor the conditions that are subject to the guarantees and indemnifications, as required under the previously existing generally accepted accounting principles, to identify if a loss has occurred. If the Company determines it is probable a loss has occurred, then any estimable loss would be recognized under those guarantees and indemnifications. Under its customer agreements, the Company may agree to indemnify, defend, and hold harmless its customers from and against certain losses, damages, and costs arising from claims alleging that the use of its software infringes the intellectual property of a third-party. Historically, the Company has not been required to pay material amounts in connection with claims asserted under these provisions, and accordingly, the Company has not recorded a liability relating to such provisions. Under its customer agreements, the Company also may represent and warrant to customers that its software will operate substantially in conformance with its documentation, and that the services the Company performs will be performed in a workmanlike manner by personnel reasonably qualified by experience and expertise to perform their assigned tasks. Historically, only minimal costs have been incurred relating to the satisfaction of warranty claims. In addition, from time to time, the Company may guarantee the performance of a contract on behalf of one or more of its subsidiaries, or a subsidiary may guarantee the performance of a contract on behalf of another subsidiary. Other guarantees include promises to indemnify, defend, and hold harmless the Company’s executive officers, directors, and certain other key officers. The Company’s certificate of incorporation provides that it will indemnify and advance expenses to its directors and officers to the maximum extent permitted by Delaware law. The indemnification covers any expenses and liabilities reasonably incurred by a person, by reason of the fact that such person is, was, or has agreed to be a director or officer, in connection with the investigation, defense, and settlement of any threatened, pending, or completed action, suit, proceeding, or claim. The Company’s certificate of incorporation authorizes the use of indemnification agreements, and the Company enters into such agreements with its directors and certain officers from time to time. These indemnification agreements typically provide for a broader scope of the Company’s obligation to indemnify the directors and officers than set forth in the certificate of incorporation. The Company’s contractual indemnification obligations under these agreements are in addition to the respective directors’ and officers’ rights under the certificate of incorporation or under Delaware law. Pending and Threatened Legal Proceedings In April 2021, ACH files associated with one of the Company's mortgage servicing customers were inadvertently transmitted into the ACH network during a test of the Company's payment processing system. The Company took immediate corrective action and issued reversing ACH files, restoring affected accounts. The Company was named as a defendant in seven class action lawsuits filed in various federal courts purportedly on behalf of consumers whose mortgage accounts were affected by the inadvertent ACH file transmission. The Company settled these lawsuits by establishing a $5.0 million fund out of which payments were to be made to class members and for attorneys’ fees and administrative costs. The $5.0 million was funded from insurance. The inadvertent ACH file transmission also gave rise to investigations by the U.S. Consumer Financial Protection Bureau (the "CFPB") and state attorneys general in all 50 states, the District of Columbia, and certain U.S. territories as well as money transmission regulators in most of those jurisdictions. The Company settled the CFPB investigation for $25.0 million plus various undertakings. Payment was made to the CFPB from funds received from the insurance carriers during the year ended December 31, 2023. The Company also settled with the state money transmission regulators and attorneys general for a total of $20.0 million plus various undertakings. Funds for the state and money transmission regulator settlements, which were previously received from the insurance carriers and deposited into an escrow account, were paid during the year ended December 31, 2023. The Company believes that the CPFB and state undertakings will not adversely affect it. The Company’s customer commenced an action for damages as a result of this event. The customer action remains pending and the Company presently intends to vigorously defend it. The Company expects that insurance will fund payments and costs associated with the defense of the customer action, and other claims that may be asserted against it, subject to the policy limits and other terms of the applicable policies. Funds received from or expected to be received from insurance carriers are generally subject to the respective carriers' reservation of rights. The Company is from time to time subject to other claims, litigation and investigations. While the Company believes that none of the currently pending matters is reasonably likely to have a material adverse effect on it, there can be no assurance with respect thereto or future matters.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company offers various defined contribution plans for our U.S. and non-U.S. employees. Total defined contribution plan expense was $12.8 million, $13.4 million, and $13.0 million during the years ended December 31, 2023, 2022, and 2021, respectively. ACI 401(k) Plan The ACI 401(k) Plan is a defined contribution plan covering all domestic employees of the Company. Participants may contribute up to 75% of their annual eligible compensation up to a maximum of $22,500 (for employees who are under the age of 50 on December 31, 2023) or a maximum of $30,000 (for employees aged 50 or older on December 31, 2023). After one year of service, the Company matches 100% of the first 4% of eligible participant contributions and 50% of the next 4% of eligible participant contributions, not to exceed $5,000 per employee annually. Company contributions charged to expense were $5.0 million, $6.2 million, and $6.0 million during the years ended December 31, 2023, 2022, and 2021, respectively. ACI Worldwide EMEA Group Personal Pension Scheme The ACI Worldwide EMEA Group Personal Pension Scheme is a defined contribution plan covering substantially all ACI Worldwide (EMEA) Limited (“ACI-EMEA”) employees. For those ACI-EMEA employees who elect to participate in the plan, the Company contributes a minimum of 8.5% of eligible compensation to the plan for employees employed at December 1, 2000 or from 7% to 10% of eligible compensation for employees employed subsequent to December 1, 2000. ACI-EMEA contributions charged to expense were $1.7 million, $1.6 million, and $1.6 million, during the years ended December 31, 2023, 2022, and 2021, respectively.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net income	$ 121,509	$ 142,177	$ 127,791

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Nature of Business and Summar_2

Nature of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Nature of Business	Nature of Business ACI Worldwide, Inc., a Delaware corporation, and its subsidiaries (collectively referred to as “ACI” or the “Company”) develop, market, install, and support a broad line of software products and services primarily focused on facilitating electronic payments. In addition to its own products, the Company distributes or acts as a sales agent for software developed by third parties. These products and services are used principally by banks and intermediaries, merchants, and billers, both in domestic and international markets.
Consolidated Financial Statements	Consolidated Financial Statements
Capital Stock	Capital Stock The Company’s outstanding capital stock consists of a single class of common stock. Each share of common stock is entitled to one vote for each matter subject to a stockholder’s vote and to dividends, if and when declared by the board of directors (the “board”).
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions are affected by management’s application of accounting policies, as well as uncertainty in the current economic environment. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents
Settlement Assets and Liabilities	Settlement Assets and Liabilities Individuals and businesses settle their obligations to the Company’s various Biller clients using credit or debit cards or via automated clearing house (“ACH”) payments. The Company creates a receivable for the amount due from the credit or debit card processor and an offsetting payable to the client. Upon confirmation that the funds have been received, the Company settles the obligation to the client. Due to timing, in some instances, the Company may (1) receive the funds into bank accounts controlled by and in the Company’s name that are not disbursed to its clients by the end of the day, resulting in a settlement deposit on the Company’s books and (2) disburse funds to its clients in advance of receiving funds from the credit or debit card processor, resulting in a net settlement receivable position.
Off Balance Sheet Settlement Accounts	Off Balance Sheet Settlement Accounts
Property and Equipment	Property and Equipment
Software	Software Software may be for internal use or for resale. Costs related to certain software, which is for resale, are capitalized in accordance with Accounting Standards Codification (“ASC”) 985-20, Costs of Software to be Sold, Leased, or Marketed , when the resulting product reaches technological feasibility. The Company generally determines technological feasibility when it has a detailed program design that takes product function, feature and technical requirements to their most detailed, logical form and is ready for coding. The Company does not typically capitalize costs related to software for resale as technological feasibility generally coincides with general availability of the software. The Company capitalizes the costs of software developed or obtained for internal use in accordance with ASC 350-40, Internal Use Software . The Company expenses all costs incurred during the preliminary project stage of its development and capitalizes the costs incurred during the application development stage. Costs incurred relating to upgrades and enhancements to the software are capitalized if it is determined that these upgrades or enhancements add additional functionality to the software. Costs incurred during the application development stage include purchased software licenses, implementation costs, consulting costs, and payroll-related costs for projects that qualify for capitalization. All other costs, primarily related to maintenance and minor software fixes, are expensed as incurred. Amortization of software for resale is determined on a product-by-product basis and begins when the product is available for licensing to customers. The annual amortization is computed using the greater of (a) the ratio of current gross revenues to the total of current and future gross revenues expected to be derived from the software or (b) the straight-line method over the remaining estimated useful life of generally five three
Business Combinations	Business Combinations The Company applies the provisions of ASC 805, Business Combinations , in the accounting for its acquisitions. It requires the Company to recognize separately from goodwill the assets acquired and the liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred and the net of the acquisition date fair values of the assets acquired and the liabilities assumed. While the Company uses its best estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, it records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to our consolidated statements of operations. Critical estimates in valuing certain intangible assets include but are not limited to future expected cash flows from customer relationships, covenants not to compete and acquired developed technologies, brand awareness and market position, as well as assumptions about the period of time the brand will continue to be used in our product portfolio, and discount rates. Management’s estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and unpredictable and, as a result, actual results may differ from estimates. Other estimates associated with the accounting for acquisitions may change as additional information becomes available regarding the assets acquired and liabilities assumed.
Fair Value	Fair Value ASC 820, Fair Value Measurements and Disclosures , (“ASC 820”) defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. ASC 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 Inputs – Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. • Level 3 Inputs – Unobservable inputs for determining the fair values of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. The fair value of the Company’s Credit Agreement approximates the carrying value due to the floating interest rate (Level 2 of the fair value hierarchy). The Company measures the fair value of its Senior Notes based on Level 2 inputs, which include quoted market prices and interest rate spreads of similar securities. The fair value of the Company’s 5.750% Senior Notes due 2026 (“2026 Notes”) was $398.5 million and $390.0 million as of December 31, 2023 and 2022, respectively. The fair values of cash and cash equivalents approximate the carrying values due to the short period of time to maturity (Level 2 of the fair value hierarchy).
Goodwill and Other Intangibles	Goodwill and Other Intangibles In accordance with ASC 350, Intangibles – Goodwill and Other , the Company assesses goodwill for impairment annually during the fourth quarter of its fiscal year using October 1 balances or when there is evidence that events or changes in circumstances indicate that the carrying amount of the asset may not be recovered. The Company evaluates goodwill at the reporting unit level using the discounted cash flow valuation model and allocates goodwill to these reporting units using a relative fair value approach. During this assessment, management relies on a number of factors, including operating results, business plans, and anticipated future cash flows. The Company has identified its reportable segments, Banks, Merchants, and Billers, as the reporting units. As of December 31, 2023, the Company's goodwill balance of $1.2 billion was allocated $671.7 million to Banks, $137.3 million to Merchants, and $417.0 million to Billers. The key assumptions used in the discounted cash flow valuation model include discount rates, growth rates, cash flow projections and terminal value rates. Discount rates, growth rates, and cash flow projections are the most sensitive and susceptible to change, as they require significant management judgment. Discount rates are determined by using a weighted average cost of capital (“WACC”). The WACC considers market and industry data as well as company-specific risk factors. Operational management, considering industry and company-specific historical and projected data, develops growth rates and cash flow projections for each reporting unit. Terminal value rate determination follows common methodology of capturing the present value of perpetual cash flow estimates beyond the last projected period, assuming a constant WACC and low, long-term growth rates. If, as per the quantitative test, the estimated fair value of the reporting unit is less than the carrying amount of the reporting unit, impairment is recognized for the difference, limited to the amount of goodwill recognized for the reporting unit. The calculated fair value substantially exceeded the current carrying value for all reporting units for all periods.
Equity Method Investment	Equity Method Investment In July 2019, the Company invested $18.3 million for a 30% non-controlling financial interest in a payment technology and services company in India. The Company accounted for this investment using the equity method in accordance with ASC 323, Investments - Equity Method and Joint Ventures . The Company records its share of earnings and losses in the investment on a one-quarter lag basis. Accordingly, the Company recorded an investment of $18.5 million and $17.9 million, which is included in other noncurrent assets in the consolidated balance sheet as of December 31, 2023 and 2022, respectively.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of a long-lived asset group may not be recoverable. An impairment loss is recorded if the sum of the future cash flows expected to result from the use of the asset (undiscounted and without interest charges) is less than the carrying amount of the asset. The amount of the impairment charge is measured based upon the fair value of the asset group.
Treasury Stock	Treasury Stock The Company accounts for shares of its common stock that are repurchased without intent to retire as treasury stock. Such shares are recorded at cost and reflected separately on the consolidated balance sheets as a reduction of stockholders’ equity. The Company issues shares of treasury stock upon exercise of stock options, issuance of restricted share units, payment of earned performance shares, and for issuance of common stock pursuant to the Company’s employee stock purchase plan. For purposes of determining the cost of the treasury shares re-issued, the Company uses the average cost method.
Stock-Based Compensation Plans	Stock-Based Compensation Plans In accordance with ASC 718, Compensation – Stock Compensation, ("ASC 718") the Company recognizes stock-based compensation expense for awards that are probable of vesting on a straight-line basis over the requisite service period of the award, which is generally the vesting term. Stock-based compensation expense is recorded in operating expenses depending on where the respective individual’s compensation is recorded. To determine the grant date fair value of total shareholder return awards (“TSRs”), a Monte Carlo simulation model was used. The assumptions utilized in the Monte Carlo simulation models, as well as the description of the plans the stock-based awards are granted under, are described in further detail in Note 6, Stock-Based Compensation Plans .
Translation of Foreign Currencies	Translation of Foreign Currencies The Company’s foreign subsidiaries typically use the local currency of the countries in which they are located as their functional currency. Their assets and liabilities are translated into U.S. dollars at the exchange rates in effect at the balance sheet date. Revenues and expenses are translated at the average exchange rates during the period. Translation gains and losses are reflected in the consolidated financial statements as a component of accumulated other comprehensive income (loss). Transaction gains and losses, including those related to intercompany accounts, that are not considered to be of a long-term investment nature are included in the determination of net income. Transaction gains and losses, including those related to intercompany accounts, that are considered to be of a long-term investment nature are reflected in the consolidated financial statements as a component of accumulated other comprehensive income (loss).
Income Taxes	Income Taxes The provision for income taxes is computed using the asset and liability method, under which deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company periodically assesses its tax exposures and establishes, or adjusts, estimated unrecognized tax benefits for probable assessments by taxing authorities, including the Internal Revenue Service, and various foreign and state authorities. Such unrecognized tax benefits represent the estimated provision for income taxes expected to ultimately be paid.
Recently Issued Accounting Standards Not Yet Effective	Recently Issued Accounting Standards Not Yet Effective In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures , to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for annual periods beginning after December 15, 2023 and interim periods beginning after December 15, 2024, and early application is permitted. The Company is currently assessing the impact the adoption of ASU 2023-07 will have on its segment reporting disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this update will require disclosure of more disaggregated information about a reporting entity's effective tax rate reconciliation and income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024, and early application is permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently assessing the impact the adoption of ASU 2023-09 will have on its income tax disclosures.
Earnings Per Share	Basic earnings per share is computed in accordance with ASC 260, Earnings per Share, based on weighted average outstanding common shares. Diluted earnings per share is computed based on basic weighted average outstanding common shares adjusted for the dilutive effect of stock options, RSUs, and certain contingently issuable shares for which performance targets have been achieved.
Segment Information	The Company reports financial performance based on its operating segments, Banks, Merchants, and Billers, and analyzes Segment Adjusted EBITDA as a measure of segment profitability. The Company’s Chief Executive Officer is also the chief operating decision maker ("CODM"). The CODM, together with other senior management personnel, focus their review on consolidated financial information and the allocation of resources based on operating results, including revenues and Segment Adjusted EBITDA, for each segment, separate from corporate operations. No operating segments have been aggregated to form the reportable segments. Banks. ACI provides payment solutions to large and mid-size banks globally for retail banking, real time, digital, and other payment services. These solutions transform banks’ complex payment environments to speed time to market, reduce costs, and deliver a consistent experience to customers across channels while enabling them to prevent and rapidly react to fraudulent activity. In addition, they enable banks to meet the requirements of different real-time payments schemes and to quickly create differentiated products to meet consumer, business, and merchant demands. Merchants. ACI’s support of merchants globally includes Tier 1 and Tier 2 merchants, online-only merchants and the payment service providers, independent selling organizations, value-added resellers, and acquirers who service them. These customers operate in a variety of verticals, including general merchandise, grocery, hospitality, dining, transportation, and others. The Company's solutions provide merchants with a secure, omni-channel payments platform that gives them independence from third-party payment providers. They also offer secure solutions to online-only merchants that provide consumers with a convenient and seamless way to shop. Billers. Within the billers segment, ACI provides electronic bill presentment and payment (“EBPP”) services to companies operating in the consumer finance, insurance, healthcare, higher education, utility, government, and mortgage categories. The solutions enable these customers to support a wide range of payment options and provide a convenient consumer payments experience that drives consumer loyalty and increases revenue. Revenue is attributed to the reportable segments based upon customer. Expenses are attributed to the reportable segments in one of three methods: (1) direct costs of the segment, (2) labor costs that can be attributed based upon time tracking for individual projects, or (3) costs that are allocated. Allocated costs are generally marketing and sales related activities. Segment Adjusted EBITDA is the measure reported to the CODM for purposes of making decisions on allocating resources and assessing the performance of the Company’s segments, and, therefore, Segment Adjusted EBITDA is presented in conformity with ASC 280, Segment Reporting . Segment Adjusted EBITDA is defined as earnings (loss) from operations before interest, income tax expense (benefit), depreciation and amortization (“EBITDA”) adjusted to exclude net other income (expense).

Nature of Business and Summar_3

Nature of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Other Current Liabilities	Other current liabilities include the following (in thousands): December 31, 2023 2022 Vendor financed licenses $ 12,702 $ 13,525 Operating lease liabilities 9,348 11,218 Accrued interest 9,172 9,067 Royalties payable 5,199 3,726 Other 45,823 65,109 Total other current liabilities $ 82,244 $ 102,645
Schedule of Net Property and Equipment	As of December 31, 2023 and 2022, net property and equipment consisted of the following (in thousands): December 31, Useful Lives 2023 2022 Computer and office equipment 3 - 5 years $ 118,805 $ 132,133 Leasehold improvements Lesser of useful life of improvement or remaining life of lease 32,660 34,159 Building and improvements 7 - 30 years 14,492 15,061 Furniture and fixtures 7 years 8,803 10,200 Land Non-depreciable 1,185 1,785 Property and equipment, gross 175,945 193,338 Less: accumulated depreciation (138,089) (140,839) Property and equipment, net $ 37,856 $ 52,499

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Total Receivables, Net	Total receivables, net is comprised of the following (in thousands): December 31, 2023 2022 Billed receivables $ 250,423 $ 218,611 Allowance for doubtful accounts (4,295) (3,779) Billed receivables, net 246,128 214,832 Current accrued receivables, net 206,209 188,949 Long-term accrued receivables, net 313,983 297,818 Total accrued receivables, net 520,192 486,767 Total receivables, net $ 766,320 $ 701,599
Schedule of Allowance for Doubtful Accounts Receivable	The following reflects activity in the Company’s allowance for doubtful accounts receivable for the periods indicated (in thousands): Years Ended December 31, 2023 2022 2021 Balance, beginning of period $ (3,779) $ (2,861) $ (3,912) Provision (increase) decrease (526) (1,496) 1,125 Amounts written off, net of recoveries 43 389 (82) Foreign currency translation adjustments and other (33) 189 8 Balance, end of period $ (4,295) $ (3,779) $ (2,861)
Schedule of Changes in Deferred Revenue	Changes in deferred revenue were as follows (in thousands): Balance, December 31, 2021 $ 110,350 Deferral of revenue 125,865 Recognition of deferred revenue (128,700) Divestiture (21,581) Foreign currency translation (4,398) Balance, December 31, 2022 81,536 Deferral of revenue 119,741 Recognition of deferred revenue (117,420) Foreign currency translation 503 Balance, December 31, 2023 $ 84,360

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Maturities on Debt Outstanding	Maturities on debt outstanding at December 31, 2023, are as follows (in thousands): Fiscal Year Ending December 31, 2024 $ 77,900 2025 565,798 2026 400,000 2027 — 2028 — Thereafter — Total $ 1,043,698
Schedule of Total Debt	Total debt is comprised of the following (in thousands): December 31, 2023 2022 Term loans $ 519,698 $ 592,729 Revolving credit facility 124,000 105,000 5.750% Senior Notes, due August 2026 400,000 400,000 Debt issuance costs (5,694) (7,857) Total debt 1,038,004 1,089,872 Less: current portion of term loans 77,900 69,906 Less: current portion of debt issuance costs (3,495) (4,385) Total long-term debt $ 963,599 $ 1,024,351

Software and Other Intangible_2

Software and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Carrying Amount and Accumulated Amortization of Software and Other Intangible Assets	The carrying amount and accumulated amortization of the Company's software assets subject to amortization at each balance sheet date are as follows (in thousands): December 31, 2023 December 31, 2022 Gross Carrying Accumulated Amortization Net Balance Gross Carrying Accumulated Amortization Net Balance Software for internal use $ 469,325 $ (360,907) $ 108,418 $ 454,171 $ (325,062) $ 129,109 The carrying amount and accumulated amortization of the Company’s other intangible assets subject to amortization at each balance sheet date are as follows (in thousands): December 31, 2023 December 31, 2022 Gross Carrying Accumulated Amortization Net Balance Gross Carrying Accumulated Amortization Net Balance Customer relationships $ 447,654 $ (252,828) $ 194,826 $ 444,749 $ (219,057) $ 225,692 Trademarks and trade names 21,899 (21,079) 820 21,678 (18,672) 3,006 Total other intangible assets $ 469,553 $ (273,907) $ 195,646 $ 466,427 $ (237,729) $ 228,698
Schedule of Estimated Amortization Expense Based on Capitalized Intangible Assets	Based on capitalized intangible assets as of December 31, 2023, estimated amortization expense amounts in future fiscal years are as follows (in thousands): Fiscal Year Ending December 31, Software Other Intangible 2024 $ 51,384 $ 29,510 2025 36,140 21,042 2026 17,316 21,042 2027 2,530 20,764 2028 1,048 18,362 Thereafter — 84,926 Total $ 108,418 $ 195,646

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Stock Option Activity	A summary of stock option activity is as follows: Number of Shares Weighted Average Exercise Price ($) Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value of In-the-Money Options ($) Outstanding, December 31, 2022 1,221,219 $ 19.00 Exercised (343,093) 19.60 Expired (4,614) 19.63 Outstanding, December 31, 2023 873,512 $ 18.76 1.98 $ 10,345,792 Exercisable, December 31, 2023 873,512 $ 18.76 1.98 $ 10,345,792
Total Shareholder Return Awards (TSRs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Nonvested TSRs	A summary of nonvested TSRs is as follows: Number of Weighted Average Nonvested as of December 31, 2022 1,011,881 $ 39.21 Granted 233,404 26.94 Forfeited (144,474) 39.54 Change in payout rate (427,685) 30.01 Nonvested as of December 31, 2023 673,126 $ 40.73
Total Shareholder Return Awards (TSRs) | Monte Carlo Simulation Model
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Fair Value of TSRs Granted	The fair value of TSRs granted during the years ended December 31, 2023, 2022, and 2021, were estimated on the date of grant using the Monte Carlo simulation model, acceptable under ASC 718, using the following weighted-average assumptions: Years Ended December 31, 2023 2022 2021 Expected life (years) 2.9 3.1 2.8 Risk-free interest rate 3.6 % 1.5 % 0.3 % Volatility 37.1 % 40.0 % 41.2 % Expected dividend yield — — —
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Nonvested RSUs	A summary of nonvested RSUs is as follows: Number of Weighted Average Nonvested as of December 31, 2022 1,184,024 $ 30.73 Granted 1,532,978 24.87 Vested (666,026) 28.37 Forfeited (476,093) 28.15 Nonvested as of December 31, 2023 1,574,883 $ 26.81

Common Stock and Treasury Sto_2

Common Stock and Treasury Stock (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Schedule of Treasury Shares Issued by Award Type	Treasury shares issued by award type are as follows: Years Ended December 31, 2023 2022 2021 Stock options 343,093 406,230 546,192 LTIP performance shares — — 10,457 TSRs — 212,210 782,588 RSUs 666,026 534,759 522,618 ESPP 140,992 145,909 120,937 Total treasury shares issued 1,150,111 1,299,108 1,982,792

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Reconciliation of Weighted Average Share Amounts used to Compute Both Basic and Diluted Earnings Per Share	The following table reconciles the weighted average share amounts used to compute both basic and diluted earnings per share (in thousands): Years Ended December 31, 2023 2022 2021 Weighted average shares outstanding: Basic weighted average shares outstanding 108,497 113,700 117,407 Add: Dilutive effect of stock options, RSUs, and contingently issuable shares 360 538 1,240 Diluted weighted average shares outstanding 108,857 114,238 118,647

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Schedule of Selected Financial Data by Reportable Segment	The following is selected financial data for the Company’s reportable segments for the periods indicated (in thousands): Years Ended December 31, 2023 2022 2021 Revenues Banks $ 616,051 $ 638,585 $ 625,125 Merchants 150,616 153,905 152,988 Billers 685,912 629,411 592,485 Total revenue $ 1,452,579 $ 1,421,901 $ 1,370,598 Segment Adjusted EBITDA Banks $ 355,489 $ 371,017 $ 372,949 Merchants 44,345 49,029 54,266 Billers 142,343 107,371 129,048 Depreciation and amortization (122,373) (127,328) (133,393) Stock-based compensation expense (24,547) (29,753) (27,242) Corporate and unallocated expenses (174,849) (166,501) (185,731) Interest, net (64,271) (40,646) (33,538) Other, net (8,510) 43,446 (1,294) Income before income taxes $ 147,627 $ 206,635 $ 175,065
Schedule of Revenue by Primary Solution Category for Reportable Segments	The following is revenue by primary solution category for the Company’s reportable segments for the periods indicated (in thousands): Year Ended December 31, 2023 Banks Merchants Billers Total Primary Solution Categories Bill Payments $ — $ — $ 685,912 $ 685,912 Digital Business Banking 2,792 — — 2,792 Merchant Payments — 150,616 — 150,616 Fraud Management 63,503 — — 63,503 Real-Time Payments 128,957 — — 128,957 Issuing and Acquiring 420,799 — — 420,799 Total $ 616,051 $ 150,616 $ 685,912 $ 1,452,579 Year Ended December 31, 2022 Banks Merchants Billers Total Primary Solution Categories Bill Payments $ — $ — $ 629,411 $ 629,411 Digital Business Banking 35,504 — — 35,504 Merchant Payments — 153,905 — 153,905 Fraud Management 47,421 — — 47,421 Real-Time Payments 104,777 — — 104,777 Issuing and Acquiring 450,883 — — 450,883 Total $ 638,585 $ 153,905 $ 629,411 $ 1,421,901 Year Ended December 31, 2021 Banks Merchants Billers Total Primary Solution Categories Bill Payments $ — $ — $ 592,485 $ 592,485 Digital Business Banking 60,398 — — 60,398 Merchant Payments — 152,988 — 152,988 Fraud Management 43,704 — — 43,704 Real-Time Payments 77,922 — — 77,922 Issuing and Acquiring 443,101 — — 443,101 Total $ 625,125 $ 152,988 $ 592,485 $ 1,370,598 The following is revenue by the Company's reportable segments for the periods indicated (in thousands): Year Ended December 31, 2023 2022 2021 Banks Software as a service and platform as a service $ 39,803 $ 48,932 $ 57,339 License 311,549 336,028 310,758 Maintenance 189,650 184,017 193,332 Services 75,049 69,608 63,696 Total $ 616,051 $ 638,585 $ 625,125 Merchants Software as a service and platform as a service $ 123,528 $ 124,631 $ 124,933 License 9,675 12,106 9,015 Maintenance 15,322 15,934 16,846 Services 2,091 1,234 2,194 Total $ 150,616 $ 153,905 $ 152,988 Billers Software as a service and platform as a service $ 685,816 $ 629,317 $ 592,070 License — — 94 Maintenance 96 94 321 Services — — — Total $ 685,912 $ 629,411 $ 592,485
Schedule of Revenue by Geographic Areas	The following is the Company's revenue by geographic location for the periods indicated (in thousands): Year Ended December 31, 2023 2022 2021 Revenue United States $ 887,168 $ 851,712 $ 869,081 Other 565,411 570,189 501,517 Total $ 1,452,579 $ 1,421,901 $ 1,370,598
Schedule of Long-lived Assets by Geographic Location	The following is the Company’s long-lived assets by geographic location for the periods indicated (in thousands): December 31, 2023 2022 Long-lived Assets United States $ 1,216,158 $ 1,286,505 Other 763,437 754,847 Total $ 1,979,595 $ 2,041,352

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Components of Income (Loss) Before Income Taxes	For financial reporting purposes, income (loss) before income taxes includes the following components (in thousands): Years Ended December 31, 2023 2022 2021 United States $ (8,342) $ (11,751) $ 69,817 Foreign 155,969 218,386 105,248 Total $ 147,627 $ 206,635 $ 175,065
Schedule of Expense (Benefit) for Income Taxes	The expense (benefit) for income taxes consists of the following (in thousands): Years Ended December 31, 2023 2022 2021 Federal Current $ (3,490) $ 7,064 $ 3,994 Deferred (6,306) (353) 6,067 Total (9,796) 6,711 10,061 State Current (2,327) 7,993 7,592 Deferred 797 (3,500) (1,498) Total (1,530) 4,493 6,094 Foreign Current 36,020 47,798 31,955 Deferred 1,424 5,456 (836) Total 37,444 53,254 31,119 Total $ 26,118 $ 64,458 $ 47,274
Schedule of Differences Between Income Tax Expense Computed at Statutory Federal Income Tax Rate and Per Consolidated Statements of Operations	Differences between the income tax expense computed at the statutory federal income tax rate and per the consolidated statements of operations are summarized as follows (in thousands): Years Ended December 31, 2023 2022 2021 Tax expense at federal rate of 21% $ 31,002 $ 43,393 $ 36,764 State income taxes, net of federal benefit 1,744 2,351 4,816 Change in valuation allowance 1,588 71 1,228 Foreign tax rate differential (7,658) (12,949) (5,376) Unrecognized tax benefit increase (decrease) (5,726) 2,039 858 Tax effect of foreign operations 10,350 15,336 16,151 Tax benefit of research & development (5,104) (3,365) (4,123) Performance-based compensation 3,004 2,266 (1,887) Tax effect of divestiture (2,900) 14,522 — Other (182) 794 (1,157) Income tax provision $ 26,118 $ 64,458 $ 47,274
Schedule of Deferred Tax Assets and Liabilities	The deferred tax assets and liabilities result from differences in the timing of the recognition of certain income and expense items for tax and financial accounting purposes. The sources of these differences at each balance sheet date are as follows (in thousands): December 31, 2023 2022 Deferred income tax assets: Net operating loss carryforwards $ 15,409 $ 16,763 Tax credits 23,197 18,497 Compensation 15,478 15,272 Deferred revenue 9,873 10,168 Operating lease 8,297 10,202 Capitalized research and development 16,903 23,891 Deferred interest 17,822 6,829 Other 951 2,704 Gross deferred income tax assets 107,930 104,326 Less: valuation allowance (12,963) (11,384) Net deferred income tax assets $ 94,967 $ 92,942 Deferred income tax liabilities: Depreciation and amortization $ (31,741) $ (33,692) Operating lease right-of-use asset (7,303) (8,885) Unbilled revenue (5,407) (9,566) Withholding tax liability (32,752) (27,432) Total deferred income tax liabilities (77,203) (79,575) Net deferred income taxes $ 17,764 $ 13,367 Deferred income taxes / liabilities included in the balance sheet are: Deferred income tax asset – noncurrent $ 58,499 $ 53,738 Deferred income tax liability – noncurrent (40,735) (40,371) Net deferred income taxes $ 17,764 $ 13,367
Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31 is as follows (in thousands): 2023 2022 2021 Balance of unrecognized tax benefits at beginning of year $ 26,408 $ 24,510 $ 24,310 Increases for tax positions of prior years 1,568 2,349 1,533 Decreases for tax positions of prior years (6,560) (3,659) (65) Increases for tax positions established for the current period 3,941 9,320 2,272 Decreases for settlements with taxing authorities (532) (63) (620) Reductions resulting from lapse of applicable statute of limitation (4,005) (5,833) (2,876) Adjustment resulting from foreign currency translation 69 (216) (44) Balance of unrecognized tax benefits at end of year $ 20,889 $ 26,408 $ 24,510

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Components of Lease Cost	The components of lease cost are as follows (in thousands): Years Ended December 31, 2023 2022 2021 Operating lease cost $ 13,074 $ 12,506 $ 12,369 Variable lease cost 2,663 2,771 3,140 Total lease cost $ 15,737 $ 15,277 $ 15,509
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases is as follows (in thousands): Years Ended December 31, 2023 2022 2021 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 14,039 $ 14,020 $ 19,623 Right-of-use assets obtained in exchange for new lease obligations: Operating leases $ 6,359 $ 7,693 $ 20,944
Schedule of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases is as follows (in thousands, except lease term and discount rate): December 31, 2023 2022 Assets: Operating lease right-of-use assets $ 34,338 $ 40,031 Liabilities: Other current liabilities $ 9,348 $ 11,218 Operating lease liabilities 29,074 33,910 Total operating lease liabilities $ 38,422 $ 45,128 Weighted average remaining operating lease term (years) 5.31 5.53 Weighted average operating lease discount rate 3.47 % 3.21 %
Schedule of Maturities on Lease Liabilities	Maturities on lease liabilities as of December 31, 2023, are as follows (in thousands): Fiscal Year Ending December 31, 2024 $ 10,465 2025 8,162 2026 6,290 2027 5,580 2028 4,801 Thereafter 6,363 Total lease payments 41,661 Less: imputed interest 3,239 Total lease liability $ 38,422

Nature of Business and Summar_4

Nature of Business and Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2019 USD ($)	Dec. 31, 2023 USD ($) vote	Dec. 31, 2022 USD ($)
Summary of Significant Accounting Policies [Line Items]
Common stock, number of votes | vote		1
Amount of off balance sheet settlement funds		$ 273,200	$ 328,700
Goodwill		1,226,026	1,226,026
Banks
Summary of Significant Accounting Policies [Line Items]
Goodwill		671,700
Merchants
Summary of Significant Accounting Policies [Line Items]
Goodwill		137,300
Billers
Summary of Significant Accounting Policies [Line Items]
Goodwill		$ 417,000
Level 2 | Senior Notes | 5.750% Senior Notes due 2026
Summary of Significant Accounting Policies [Line Items]
Stated interest rate (percentage)		5.75%
Fair value of long-term debt		$ 398,500	390,000
India Payment Technology and Services Company
Summary of Significant Accounting Policies [Line Items]
Payments to acquire investment interest	$ 18,300
Percentage of voting interests acquired	30%
India Payment Technology and Services Company | Other Noncurrent Assets
Summary of Significant Accounting Policies [Line Items]
Equity method investment, carrying amount		$ 18,500	$ 17,900
Software for Resale | Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		5 years
Software for Resale | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		10 years
Software for internal use | Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		3 years
Software for internal use | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		8 years
Other Intangible Assets | Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		4 years
Other Intangible Assets | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		20 years

Nature of Business and Summar_5

Nature of Business and Summary of Significant Accounting Policies - Schedule of Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Other Current Liabilities
Vendor financed licenses	$ 12,702	$ 13,525
Operating lease liabilities	9,348	11,218
Accrued interest	9,172	9,067
Royalties payable	5,199	3,726
Other	45,823	65,109
Total other current liabilities	$ 82,244	$ 102,645

Nature of Business and Summar_6

Nature of Business and Summary of Significant Accounting Policies - Schedule of Net Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 175,945	$ 193,338
Less: accumulated depreciation	(138,089)	(140,839)
Property and equipment, net	37,856	52,499
Computer and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 118,805	132,133
Computer and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	3 years
Computer and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 32,660	34,159
Building and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,492	15,061
Building and improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	7 years
Building and improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	30 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful Lives	7 years
Property and equipment, gross	$ 8,803	10,200
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,185	$ 1,785

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenue [Line Items]
Software license arrangements, warranty period	90 days
Software license arrangements, initial post contract customer support period	1 year
Revenue allocated to remaining performance obligations	$ 665.6
Performance obligation satisfied in previous periods	$ 79
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue [Line Items]
Revenue allocated to remaining performance obligations, percentage to be recognized	50%
Timing of revenue to be collected	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue [Line Items]
Timing of revenue to be collected
Customer Concentration Risk | Revenue Benchmark | Significant Customer
Revenue [Line Items]
Concentration risk, percentage		10.10%
Costs to Obtain a Contract
Revenue [Line Items]
Capitalized costs to obtain or fulfill a contract, minimum amortization period	1 year
Capitalized costs to obtain or fulfill a contract, current	$ 3.3	$ 1.5
Capitalized costs to obtain or fulfill a contract, noncurrent	13.9	14.5
Costs to Obtain a Contract | Selling and Marketing
Revenue [Line Items]
Capitalized costs to obtain or fulfill a contract, amortization expense	8.7	8.3
Costs to Fulfill a Contract
Revenue [Line Items]
Capitalized costs to obtain or fulfill a contract, current	0.1	0.1
Capitalized costs to obtain or fulfill a contract, noncurrent	9.7	9.7
Costs to Fulfill a Contract | Cost of Revenue
Revenue [Line Items]
Capitalized costs to obtain or fulfill a contract, amortization expense	$ 3.6	$ 3.1

Revenue - Schedule of Total Rec

Revenue - Schedule of Total Receivables, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Billed receivables	$ 250,423	$ 218,611
Allowance for doubtful accounts	(4,295)	(3,779)	$ (2,861)	$ (3,912)
Billed receivables, net	246,128	214,832
Current accrued receivables, net	206,209	188,949
Long-term accrued receivables, net	313,983	297,818
Total accrued receivables, net	520,192	486,767
Total receivables, net	$ 766,320	$ 701,599

Revenue - Schedule of Allowance

Revenue - Schedule of Allowance for Doubtful Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ (3,779)	$ (2,861)	$ (3,912)
Provision (increase) decrease	(526)	(1,496)	1,125
Amounts written off, net of recoveries	43	389	(82)
Foreign currency translation adjustments and other	(33)	189	8
Balance, end of period	$ (4,295)	$ (3,779)	$ (2,861)

Revenue - Schedule of Changes i

Revenue - Schedule of Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Change in Contract with Customer, Liability [Roll Forward]
Deferred revenue, beginning balance	$ 81,536	$ 110,350
Deferral of revenue	119,741	125,865
Recognition of deferred revenue	(117,420)	(128,700)
Divestiture		(21,581)
Foreign currency translation	503	(4,398)
Deferred revenue, ending balance	$ 84,360	$ 81,536

Divestiture (Details)

Divestiture (Details) - Discontinued Operations, Disposed of by Sale - One Equity Partners - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Jun. 07, 2022
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Divestiture consideration received			$ 100
Net after-tax gain sale	$ 0.5	$ 38.5

Debt - Narrative (Details)

Debt - Narrative (Details)			12 Months Ended
	Apr. 28, 2023	Apr. 05, 2019 USD ($)	Dec. 31, 2023 USD ($) Agreement	Dec. 31, 2019	Feb. 26, 2024 USD ($)	Dec. 31, 2022 USD ($)	Aug. 12, 2020 USD ($)	Aug. 21, 2018 USD ($)	Feb. 24, 2017
Debt Instrument [Line Items]
Long-term debt, amount outstanding			$ 1,043,698,000
Credit Agreement
Debt Instrument [Line Items]
Extension term	1 year
Effective interest rate (percentage)			7.21%
Number of letter of credit agreements | Agreement			3
Credit Agreement | Maximum
Debt Instrument [Line Items]
Consolidated total net leverage ratio		5							4.25
Credit Agreement | Parent Company and Domestic Subsidiaries
Debt Instrument [Line Items]
Percentage of capital stock pledged as collateral			100%
Credit Agreement | Foreign Subsidiaries
Debt Instrument [Line Items]
Percentage of capital stock pledged as collateral			65%
Credit Agreement | Federal Funds Effective Swap Rate | Option (a)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.50%
Credit Agreement | Secured Overnight Financing Rate (SOFR) | Option (a)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			1%
Credit Agreement | Secured Overnight Financing Rate (SOFR) | Option (b) | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.25%
Credit Agreement | Secured Overnight Financing Rate (SOFR) | Option (b) | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			1.25%
Credit Agreement | Base Rate | Option (a) | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			1.25%
Credit Agreement | Base Rate | Option (a) | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.25%
Revolving Credit Facility | Credit Agreement
Debt Instrument [Line Items]
Line of credit, amount outstanding			$ 124,000,000
Unused borrowings			373,900,000
Debt instrument, term		5 years
Credit facility, maximum borrowing capacity		$ 500,000,000					$ 497,900,000
Revolving Credit Facility | Credit Agreement | Letter of Credit
Debt Instrument [Line Items]
Unused borrowings			$ 2,100,000
Debt instrument, term			1 year
Delayed Draw Term Loan | Credit Agreement
Debt Instrument [Line Items]
Debt instrument, face amount		$ 500,000,000
Debt instrument, term		5 years
Term Loans | Credit Agreement
Debt Instrument [Line Items]
Long-term debt, amount outstanding			$ 519,700,000
Term Loans | Credit Agreement | Maximum
Debt Instrument [Line Items]
Consolidated senior secured net leverage ratio		3.75							3.50
Initial Term Loan | Credit Agreement
Debt Instrument [Line Items]
Debt instrument, face amount		$ 279,000,000
Debt instrument, term		5 years
Senior Notes | 5.750% Senior Notes, due August 2026
Debt Instrument [Line Items]
Long-term debt, amount outstanding			400,000,000
Debt instrument, face amount								$ 400,000,000
Issue price percentage of senior notes of the principal amount								100%
Stated interest rate (percentage)								5.75%
Line of Credit | Revolving Credit Facility | Refinance Amendment | Subsequent Event
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity					$ 600,000,000
Line of Credit | Term Loan | Refinance Amendment | Subsequent Event
Debt Instrument [Line Items]
Debt instrument, face amount					$ 500,000,000
Line of Credit | Overdraft Facility
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				2.25%
Line of credit facility, amount available			75,000,000
Line of credit facility, amount outstanding			0			$ 0
Other | Multi-year License Agreement
Debt Instrument [Line Items]
Debt instrument, face amount						10,700,000
Other long-term debt, amount outstanding			$ 3,600,000			9,300,000
Other | Multi-year License Agreement | Other Current Liabilities
Debt Instrument [Line Items]
Other long-term debt, amount outstanding						5,800,000
Other | Multi-year License Agreement | Other Noncurrent Liabilities
Debt Instrument [Line Items]
Other long-term debt, amount outstanding						$ 3,500,000

Debt - Schedule of Maturities o

Debt - Schedule of Maturities on Debt Outstanding (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Debt Disclosure [Abstract]
2024	$ 77,900
2025	565,798
2026	400,000
2027	0
2028	0
Thereafter	0
Total	$ 1,043,698

Debt - Schedule of Total Debt (

Debt - Schedule of Total Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Aug. 21, 2018
Debt Instrument [Line Items]
Total debt	$ 1,038,004	$ 1,089,872
Debt issuance costs	(5,694)	(7,857)
Less: current portion of term loans	74,405	65,521
Less: current portion of debt issuance costs	(3,495)	(4,385)
Total long-term debt	963,599	1,024,351
Term Loans
Debt Instrument [Line Items]
Total debt	519,698	592,729
Less: current portion of term loans	77,900	69,906
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Total debt	124,000	105,000
Senior Notes | 5.750% Senior Notes, due August 2026
Debt Instrument [Line Items]
Total debt	$ 400,000	$ 400,000
Stated interest rate (percentage)			5.75%

Software and Other Intangible_3

Software and Other Intangible Assets - Schedule of Carrying Amount and Accumulated Amortization of Software (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Net Balance	$ 195,646	$ 228,698
Software for internal use
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	469,325	454,171
Accumulated Amortization	(360,907)	(325,062)
Net Balance	$ 108,418	$ 129,109

Software and Other Intangible_4

Software and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Other intangible assets amortization expense	$ 33.8	$ 35.5	$ 37
Software for internal use
Finite-Lived Intangible Assets [Line Items]
Software amortization expense	$ 64.8	68	69.3
Software for Resale
Finite-Lived Intangible Assets [Line Items]
Software amortization expense		$ 0.7	$ 6.2

Software and Other Intangible_5

Software and Other Intangible Assets - Schedule of Carrying Amount and Accumulated Amortization of Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Net Balance	$ 195,646	$ 228,698
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	447,654	444,749
Accumulated Amortization	(252,828)	(219,057)
Net Balance	194,826	225,692
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	21,899	21,678
Accumulated Amortization	(21,079)	(18,672)
Net Balance	820	3,006
Total other intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	469,553	466,427
Accumulated Amortization	(273,907)	(237,729)
Net Balance	$ 195,646	$ 228,698

Software and Other Intangible_6

Software and Other Intangible Assets - Schedule of Estimated Amortization Expense Based on Capitalized Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Net Balance	$ 195,646	$ 228,698
Software Amortization
Finite-Lived Intangible Assets [Line Items]
2024	51,384
2025	36,140
2026	17,316
2027	2,530
2028	1,048
Thereafter	0
Net Balance	108,418
Other Intangible Assets Amortization
Finite-Lived Intangible Assets [Line Items]
2024	29,510
2025	21,042
2026	21,042
2027	20,764
2028	18,362
Thereafter	84,926
Net Balance	$ 195,646

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans - Narrative (Details) - USD ($)		12 Months Ended
	Apr. 06, 2017	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jun. 09, 2020	Dec. 31, 2016	Dec. 31, 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 24,547,000	$ 29,753,000	$ 27,242,000
Stock-based compensation expense, tax benefits		4,500,000	4,500,000	3,900,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of stock options exercised		$ 2,100,000	$ 2,900,000	11,400,000
Stock Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award		1 year
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award		10 years
LTIP Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense				$ 400,000
Stock based compensation awards, award payout range, maximum		200%
LTIP Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period		1 year
LTIP Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period		3 years
Total Shareholder Return Awards (TSRs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation awards, award payout range, maximum		200%
Vesting period			3 years	3 years
TSR multiplier		20%
Stock based compensation awards, award payout range, minimum		0%
Issued in period (in shares)		0
Unrecognized compensation costs		$ 7,800,000
Unrecognized compensation costs, weighted average recognition periods		1 year 8 months 12 days
Total Shareholder Return Awards (TSRs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Total Shareholder Return Awards (TSRs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Requisite service period		3 years
Award vesting rights, incremental vesting percentage on anniversary of grant date		100%
Number of shares vested (in shares)		666,026
Shares withheld to pay employees' portion of minimum payroll withholding taxes (in shares)		201,634
Unrecognized compensation costs		$ 32,200,000
Unrecognized compensation costs, weighted average recognition periods		2 years 1 month 6 days
Restricted Stock Units (RSUs) | Board Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares of common stock reserved for issuance (in shares)	3,000,000
Purchase of common stock under the plan, employee annual base compensation, amount	$ 25,000
Purchase of common stock under the plan, employee annual base compensation, percentage	10%
Price of common stock purchased under ESPP, percentage	85%
Discount offered pursuant to ESPP, percentage		15%
Stock-based compensation expense		$ 500,000	$ 600,000	$ 600,000
2020 Equity and Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)					6,658,754
2016 Equity and Performance Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance (in shares)						8,000,000
2005 Equity and Performance Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance (in shares)							23,250,000

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans - Schedule of Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Number of Shares
Outstanding, beginning balance (in shares) | shares	1,221,219
Exercised (in shares) | shares	(343,093)
Expired (in shares) | shares	(4,614)
Outstanding, ending balance (in shares) | shares	873,512
Exercisable, ending balance (in shares) | shares	873,512
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 19
Exercised (in dollars per share) | $ / shares	19.60
Expired (in dollars per share) | $ / shares	19.63
Ending balance (in dollars per share) | $ / shares	18.76
Weighted average exercise price, exercisable, ending balance (in dollars per share) | $ / shares	$ 18.76
Weighted Average Remaining Contractual Term (Years)
Weighted average remaining contractual term, outstanding, end of period (in years)	1 year 11 months 23 days
Weighted average remaining contractual term, exercisable, end of period (in years)	1 year 11 months 23 days
Aggregate Intrinsic Value of In-the-Money Options
Aggregate intrinsic value of in-the-money options, outstanding, end of period | $	$ 10,345,792
Aggregate intrinsic value of in-the-money options, exercisable, end of period | $	$ 10,345,792

Stock-Based Compensation Plan_4

Stock-Based Compensation Plans - Schedule of Nonvested TSRs (Details) - Total Shareholder Return Awards (TSRs)	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Number of Shares
Nonvested, beginning balance (in shares) | shares	1,011,881
Granted (in shares) | shares	233,404
Forfeited (in shares) | shares	(144,474)
Change in payout rate (in shares) | shares	(427,685)
Nonvested, ending balance (in shares) | shares	673,126
Weighted Average Grant Date Fair Value
Nonvested, beginning balance (in dollars per share) | $ / shares	$ 39.21
Granted (in dollars per share) | $ / shares	26.94
Forfeited (in dollars per share) | $ / shares	39.54
Change in payout rate (in dollars per share) | $ / shares	30.01
Nonvested, ending balance (in dollars per share) | $ / shares	$ 40.73

Stock-Based Compensation Plan_5

Stock-Based Compensation Plans - Schedule of Fair Value of TSRs Granted (Details) - Total Shareholder Return Awards (TSRs) - Monte Carlo Simulation Model	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)	2 years 10 months 24 days	3 years 1 month 6 days	2 years 9 months 18 days
Risk-free interest rate	3.60%	1.50%	0.30%
Volatility	37.10%	40%	41.20%
Expected dividend yield	0%	0%	0%

Stock-Based Compensation Plan_6

Stock-Based Compensation Plans - Schedule of Nonvested RSUs (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Number of Shares
Nonvested, beginning balance (in shares) | shares	1,184,024
Granted (in shares) | shares	1,532,978
Vested (in shares) | shares	(666,026)
Forfeited (in shares) | shares	(476,093)
Nonvested, ending balance (in shares) | shares	1,574,883
Weighted Average Grant Date Fair Value
Nonvested, beginning balance (in dollars per share) | $ / shares	$ 30.73
Granted (in dollars per share) | $ / shares	24.87
Vested (in dollars per share) | $ / shares	28.37
Forfeited (in dollars per share) | $ / shares	28.15
Nonvested, ending balance (in dollars per share) | $ / shares	$ 26.81

Common Stock and Treasury Sto_3

Common Stock and Treasury Stock - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 28, 2023
Equity [Abstract]
Repurchase program, amount approved for repurchase				$ 200,000,000
Repurchase of common stock (in shares)	939,567	8,624,238	3,000,000
Repurchase program, shares repurchased, value	$ 27,587,000	$ 206,537,000	$ 107,378,000
Repurchase program, shares repurchased to date (in shares)	58,921,300
Repurchase program, value of shares repurchased to date	$ 953,800,000
Repurchase program, maximum remaining amount authorized for purchase	$ 172,400,000

Common Stock and Treasury Sto_4

Common Stock and Treasury Stock - Schedule of Treasury Shares Issued by Award Type (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity, Class of Treasury Stock [Line Items]
Total treasury shares issued (in shares)	1,150,111	1,299,108	1,982,792
Stock options
Equity, Class of Treasury Stock [Line Items]
Total treasury shares issued (in shares)	343,093	406,230	546,192
LTIP performance shares
Equity, Class of Treasury Stock [Line Items]
Total treasury shares issued (in shares)	0	0	10,457
TSRs
Equity, Class of Treasury Stock [Line Items]
Total treasury shares issued (in shares)	0	212,210	782,588
RSUs
Equity, Class of Treasury Stock [Line Items]
Total treasury shares issued (in shares)	666,026	534,759	522,618
ESPP
Equity, Class of Treasury Stock [Line Items]
Total treasury shares issued (in shares)	140,992	145,909	120,937

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Reconciliation of Weighted Average Share Amounts used to Compute Both Basic and Diluted Earnings Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)	108,497	113,700	117,407
Add: Dilutive effect of stock options, RSUs, and contingently issuable shares (in shares)	360	538	1,240
Diluted weighted average shares outstanding (in shares)	108,857	114,238	118,647

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Antidilutive securities excluded from earnings (loss) per share, options to purchase shares, RSUs, and contingently issuable shares (in shares)	1,300,000	1,900,000	1,300,000
Common stock outstanding (in shares)	108,077,738	108,068,828

Other, Net (Details)

Other, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense), net
Other income (expense), net	$ (8,510)	$ 43,446	$ (1,294)
Discontinued Operations, Disposed of by Sale | One Equity Partners
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net after-tax gain sale	$ 500	$ 38,500

Segment Information - Schedule

Segment Information - Schedule of Selected Financial Data by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 1,452,579	$ 1,421,901	$ 1,370,598
Depreciation and amortization	(122,373)	(127,328)	(133,393)
Stock-based compensation expense	(24,547)	(29,753)	(27,242)
Corporate and unallocated expenses	(174,849)	(166,501)	(185,731)
Interest, net	(64,271)	(40,646)	(33,538)
Other, net	(8,510)	43,446	(1,294)
Income before income taxes	147,627	206,635	175,065
Operating Segments | Banks
Segment Reporting Information [Line Items]
Revenues	616,051	638,585	625,125
Segment Adjusted EBITDA	355,489	371,017	372,949
Operating Segments | Merchants
Segment Reporting Information [Line Items]
Revenues	150,616	153,905	152,988
Segment Adjusted EBITDA	44,345	49,029	54,266
Operating Segments | Billers
Segment Reporting Information [Line Items]
Revenues	685,912	629,411	592,485
Segment Adjusted EBITDA	$ 142,343	$ 107,371	$ 129,048

Segment Information - Schedul_2

Segment Information - Schedule of Revenue by Primary Solution Category for Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 1,452,579	$ 1,421,901	$ 1,370,598
Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	685,912	629,411	592,485
Digital Business Banking
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	2,792	35,504	60,398
Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	150,616	153,905	152,988
Fraud Management
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	63,503	47,421	43,704
Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	128,957	104,777	77,922
Issuing and Acquiring
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	420,799	450,883	443,101
License
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	321,224	348,134	319,867
Maintenance
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	205,068	200,045	210,499
Operating Segments | Banks
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	616,051	638,585	625,125
Operating Segments | Banks | Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Banks | Digital Business Banking
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	2,792	35,504	60,398
Operating Segments | Banks | Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Banks | Fraud Management
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	63,503	47,421	43,704
Operating Segments | Banks | Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	128,957	104,777	77,922
Operating Segments | Banks | Issuing and Acquiring
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	420,799	450,883	443,101
Operating Segments | Banks | Software as a service and platform as a service
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	39,803	48,932	57,339
Operating Segments | Banks | License
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	311,549	336,028	310,758
Operating Segments | Banks | Maintenance
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	189,650	184,017	193,332
Operating Segments | Banks | Services
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	75,049	69,608	63,696
Operating Segments | Merchants
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	150,616	153,905	152,988
Operating Segments | Merchants | Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Merchants | Digital Business Banking
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Merchants | Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	150,616	153,905	152,988
Operating Segments | Merchants | Fraud Management
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Merchants | Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Merchants | Issuing and Acquiring
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Merchants | Software as a service and platform as a service
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	123,528	124,631	124,933
Operating Segments | Merchants | License
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	9,675	12,106	9,015
Operating Segments | Merchants | Maintenance
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	15,322	15,934	16,846
Operating Segments | Merchants | Services
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	2,091	1,234	2,194
Operating Segments | Billers
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	685,912	629,411	592,485
Operating Segments | Billers | Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	685,912	629,411	592,485
Operating Segments | Billers | Digital Business Banking
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Billers | Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Billers | Fraud Management
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Billers | Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Billers | Issuing and Acquiring
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	0
Operating Segments | Billers | Software as a service and platform as a service
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	685,816	629,317	592,070
Operating Segments | Billers | License
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	0	94
Operating Segments | Billers | Maintenance
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	96	94	321
Operating Segments | Billers | Services
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 0	$ 0	$ 0

Segment Information - Schedul_3

Segment Information - Schedule of Revenues and Long-lived Assets by Geographic Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 1,452,579	$ 1,421,901	$ 1,370,598
Long-lived Assets
Total	1,979,595	2,041,352
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	887,168	851,712	869,081
Long-lived Assets
Total	1,216,158	1,286,505
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	565,411	570,189	$ 501,517
Long-lived Assets
Total	$ 763,437	$ 754,847

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (8,342)	$ (11,751)	$ 69,817
Foreign	155,969	218,386	105,248
Income before income taxes	$ 147,627	$ 206,635	$ 175,065

Income Taxes - Schedule of Expe

Income Taxes - Schedule of Expense (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Federal
Current	$ (3,490)	$ 7,064	$ 3,994
Deferred	(6,306)	(353)	6,067
Total	(9,796)	6,711	10,061
State
Current	(2,327)	7,993	7,592
Deferred	797	(3,500)	(1,498)
Total	(1,530)	4,493	6,094
Foreign
Current	36,020	47,798	31,955
Deferred	1,424	5,456	(836)
Total	37,444	53,254	31,119
Income tax provision	$ 26,118	$ 64,458	$ 47,274

Income Taxes - Schedule of Diff

Income Taxes - Schedule of Differences Between Income Tax Expense Computed at Statutory Federal Income Tax Rate and Per Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax expense at federal rate of 21%	$ 31,002	$ 43,393	$ 36,764
State income taxes, net of federal benefit	1,744	2,351	4,816
Change in valuation allowance	1,588	71	1,228
Foreign tax rate differential	(7,658)	(12,949)	(5,376)
Unrecognized tax benefit increase (decrease)	(5,726)	2,039	858
Tax effect of foreign operations	10,350	15,336	16,151
Tax benefit of research & development	(5,104)	(3,365)	(4,123)
Performance-based compensation	3,004	2,266	(1,887)
Tax effect of divestiture	(2,900)	14,522	0
Other	(182)	794	(1,157)
Income tax provision	$ 26,118	$ 64,458	$ 47,274

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred income tax assets:
Net operating loss carryforwards	$ 15,409	$ 16,763
Tax credits	23,197	18,497
Compensation	15,478	15,272
Deferred revenue	9,873	10,168
Operating lease	8,297	10,202
Capitalized research and development	16,903	23,891
Deferred interest	17,822	6,829
Other	951	2,704
Gross deferred income tax assets	107,930	104,326
Less: valuation allowance	(12,963)	(11,384)
Net deferred income tax assets	94,967	92,942
Deferred income tax liabilities:
Depreciation and amortization	(31,741)	(33,692)
Operating lease right-of-use asset	(7,303)	(8,885)
Unbilled revenue	(5,407)	(9,566)
Withholding tax liability	(32,752)	(27,432)
Total deferred income tax liabilities	(77,203)	(79,575)
Net deferred income taxes	17,764	13,367
Deferred income taxes / liabilities included in the balance sheet are:
Deferred income tax asset – noncurrent	58,499	53,738
Deferred income tax liability – noncurrent	(40,735)	(40,371)
Net deferred income taxes	$ 17,764	$ 13,367

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Line Items]
Deferred interest from reclassification			$ 6,800
Income Tax Uncertainties:
Deferred tax liability undistributed earnings of foreign subsidiaries		$ 600	1,300
Unrecognized tax benefit		20,889	26,408	$ 24,510	$ 24,310
Net unrecognized tax benefits that, if recognized, would favorably impact the effective income tax rate		20,100	25,000
Foreign tax credit regulation, tax benefit	$ 6,000
Decrease in unrecognized tax benefits due to the settlement of various audits and the expiration of statutes of limitations		2,200
Accrued interest and penalties related to income tax liabilities		500	600
Aggregate amount of interest and penalties expense (benefit) recorded in the statement of operations		(100)	(500)	$ (100)
INDIA
Income Tax Uncertainties:
Undistributed earnings		41,500
Non-US, Excluding India
Income Tax Uncertainties:
Undistributed earnings		23,400
Other Noncurrent Liabilities
Income Tax Uncertainties:
Unrecognized tax benefit		10,500	$ 19,900
Domestic Federal
Operating Loss Carryforwards:
Operating loss carryforwards		47,900
Operating loss carryforwards, not subject to expiration		2,900
Domestic Federal | General Business Tax Credit Carryforward
Tax Credit Carryforward:
Tax credit carryforward		27,400
State
Operating Loss Carryforwards:
Operating loss carryforwards, deferred tax asset, subject to expiration		900
Operating loss carryforwards, valuation allowance		500
State | General Business Tax Credit Carryforward
Tax Credit Carryforward:
Tax credit carryforward		600
Foreign
Operating Loss Carryforwards:
Operating loss carryforwards		16,700
Operating loss carryforwards, not subject to expiration		$ 16,500
Operating loss carryforwards, expiration period		5 years
Tax Credit Carryforward:
Tax credit carryforward		$ 2,200
Tax credit carryforward, valuation allowance		2,200
Other Foreign Jurisdiction
Tax Credit Carryforward:
Tax credit carryforward		3,300
Tax credit carryforward, valuation allowance		1,000
Tax credit carryforward, not subject to expiration		$ 1,000
Tax credit carryforward, expiration period		7 years

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits
Balance of unrecognized tax benefits at beginning of year	$ 26,408	$ 24,510	$ 24,310
Increases for tax positions of prior years	1,568	2,349	1,533
Decreases for tax positions of prior years	(6,560)	(3,659)	(65)
Increases for tax positions established for the current period	3,941	9,320	2,272
Decreases for settlements with taxing authorities	(532)	(63)	(620)
Reductions resulting from lapse of applicable statute of limitation	(4,005)	(5,833)	(2,876)
Adjustment resulting from foreign currency translation	69	(216)	(44)
Balance of unrecognized tax benefits at end of year	$ 20,889	$ 26,408	$ 24,510

Leases - Narrative (Details)

Leases - Narrative (Details)	12 Months Ended
	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Option to terminate, term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal option, term	25 years

Leases - Schedule of Components

Leases - Schedule of Components of Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 13,074	$ 12,506	$ 12,369
Variable lease cost	2,663	2,771	3,140
Total lease cost	$ 15,737	$ 15,277	$ 15,509

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 14,039	$ 14,020	$ 19,623
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	$ 6,359	$ 7,693	$ 20,944

Leases - Schedule of Suppleme_2

Leases - Schedule of Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Assets:
Operating lease right-of-use assets	$ 34,338	$ 40,031
Liabilities:
Other current liabilities	9,348	11,218
Operating lease liabilities	29,074	33,910
Total operating lease liabilities	$ 38,422	$ 45,128
Weighted average remaining operating lease term (years)	5 years 3 months 21 days	5 years 6 months 10 days
Weighted average operating lease discount rate	3.47%	3.21%

Leases - Schedule of Maturities

Leases - Schedule of Maturities on Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 10,465
2025	8,162
2026	6,290
2027	5,580
2028	4,801
Thereafter	6,363
Total lease payments	41,661
Less: imputed interest	3,239
Total lease liability	$ 38,422	$ 45,128

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) lawsuit
U.S. Consumer Financial Protection Bureau and State Attorneys General | Settled Litigation
Loss Contingencies [Line Items]
BHMI settlement and related fees	$ 25
State Money Transmission Regulators and State Attorneys General | Settled Litigation
Loss Contingencies [Line Items]
BHMI settlement and related fees	$ 20
ACH File Transmission
Loss Contingencies [Line Items]
Number of class action lawsuits filed | lawsuit	7
BHMI settlement and related fees	$ 5

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, cost	$ 12,800,000	$ 13,400,000	$ 13,000,000
ACI 401(k) Plan
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, cost	$ 5,000,000	6,200,000	6,000,000
Defined contribution plan, maximum annual contribution per employee, percentage	75%
Defined contribution plan, service period requirement for company match	1 year
Defined contribution plan, employer matching contribution, percentage of match	100%
Defined contribution plan, employer matching contribution, percent of eligible participant contributions	4%
Defined contribution plan, employer matching contribution, maximum amount per employee	$ 5,000
ACI 401(k) Plan | Employees under Age 50
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, maximum annual contribution per employee, amount	22,500
ACI 401(k) Plan | Employees Aged 50 or Older
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, maximum annual contribution per employee, amount	$ 30,000
ACI 401(k) Plan | Second Eligible Participant Contributions
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employer matching contribution, percentage of match	50%
ACI 401(k) Plan | Second Eligible Participant Contributions | Maximum
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employer matching contribution, percent of eligible participant contributions	4%
ACI Worldwide EMEA Group Personal Pension Scheme
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, cost	$ 1,700,000	$ 1,600,000	$ 1,600,000
ACI Worldwide EMEA Group Personal Pension Scheme | Employed at December 1, 2000
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employer discretionary contribution, percentage of eligible compensation	8.50%
ACI Worldwide EMEA Group Personal Pension Scheme | Employed Subsequent to December 1, 2000 | Minimum
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employer discretionary contribution, percentage of eligible compensation	7%
ACI Worldwide EMEA Group Personal Pension Scheme | Employed Subsequent to December 1, 2000 | Maximum
Schedule Of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employer discretionary contribution, percentage of eligible compensation	10%