Segment Information - Selected Financial Data, Revenues and Long lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 291,485	$ 205,855
Long-lived assets
Long-lived assets	2,239,658		$ 2,285,547
Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	153,686	68,967
Digital Channels
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	15,956	18,513
Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	23,120	24,361
Payments Intelligence
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	13,126	16,018
Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	18,296	15,333
Retail Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	67,301	62,663
Americas - United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	204,793	119,458
Long-lived assets
Long-lived assets	1,507,574		1,526,046
Americas - Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	21,174	13,688
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	39,873	54,519
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	25,645	18,190
Other
Long-lived assets
Long-lived assets	732,084		$ 759,501
Operating Segments | ACI On Demand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	192,950	109,848
Operating Segments | ACI On Demand | Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	153,686	68,967
Operating Segments | ACI On Demand | Digital Channels
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	8,393	9,788
Operating Segments | ACI On Demand | Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	19,014	19,339
Operating Segments | ACI On Demand | Payments Intelligence
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	9,013	8,981
Operating Segments | ACI On Demand | Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	997	618
Operating Segments | ACI On Demand | Retail Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	1,847	2,155
Operating Segments | ACI On Premise
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	98,535	96,007
Operating Segments | ACI On Premise | Bill Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	0	0
Operating Segments | ACI On Premise | Digital Channels
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	7,563	8,725
Operating Segments | ACI On Premise | Merchant Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	4,106	5,022
Operating Segments | ACI On Premise | Payments Intelligence
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	4,113	7,037
Operating Segments | ACI On Premise | Real-Time Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	17,299	14,715
Operating Segments | ACI On Premise | Retail Payments
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	65,454	60,508
Operating Segments | Americas - United States | ACI On Demand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	175,654	93,036
Operating Segments | Americas - United States | ACI On Premise
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	29,139	26,422
Operating Segments | Americas - Other | ACI On Demand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	3,233	2,743
Operating Segments | Americas - Other | ACI On Premise
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	17,941	10,945
Operating Segments | EMEA | ACI On Demand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	10,918	12,068
Operating Segments | EMEA | ACI On Premise
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	28,955	42,451
Operating Segments | Asia Pacific | ACI On Demand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	3,145	2,001
Operating Segments | Asia Pacific | ACI On Premise
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 22,500	$ 16,189