Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands				3 Months Ended										12 Months Ended
	Dec. 31, 2016	Nov. 04, 2015	Aug. 12, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Percentage of ownership interest acquired	100.00%			100.00%										100.00%
Additional borrowing														$ 76,000	$ 298,000	$ 169,500
Operating Income (loss)				$ 120,343	$ (9,353)	$ (26,572)		$ 136,712		$ 73,973	$ 23,886	$ 23,664	$ 6,425	$ 221,130	$ 127,948	$ 138,172
Restricted share awards (RSAs) [Member]
Business Acquisition [Line Items]
Issuance of ACI common stock														148,322	125,026	106,275
Awards granted requisite service period														3 years	3 years	3 years
Revolving Credit Facility
Business Acquisition [Line Items]
Additional borrowing	$ 181,000		$ 60,500
Term Credit Facility [Member]
Business Acquisition [Line Items]
Additional borrowing			150,000
PAY.ON
Business Acquisition [Line Items]
Total purchase price		$ 186,141												$ 186,141
Acquisition related transaction expenses															$ 900
Revenue														16,500	2,900
Operating Income (loss)														17,100	2,100
Business acquisition cash paid														$ 180,994
PAY.ON | Restricted share awards (RSAs) [Member]
Business Acquisition [Line Items]
Issuance of ACI common stock														476,750
Fair value of shares on grant date	$ 11,300			$ 11,300										$ 11,300
Awards granted requisite service period														2 years
PAY.ON | Restricted share awards (RSAs) [Member] | Vest In Every Six Months
Business Acquisition [Line Items]
Percentage of award vesting increment for every six month														25.00%
Retail Decisions [Member]
Business Acquisition [Line Items]
Acquisition related transaction expenses																$ 2,700
Revenue															42,700	17,900
Operating Income (loss)															$ 6,800	$ 1,900
Business acquisition cash paid			$ 205,100

[1] As previously discussed in Note 1, Nature of Business and Summary of Significant Accounting Policies, the Company adopted ASU 2016-09 during the year ended December 31, 2016. The Company elected to early adopt ASU 2016-09 in the third quarter of 2016, which requires it to reflect any adjustments as of January 1, 2016, the beginning of the annual period that includes the interim period of adoption. The impact of the adoption to the Company's previously reported quarterly results for the quarters ended March 31 and June 30, 2016 are reflected in the table above.