Selected Segment Financial Data, Revenues and Operating Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 326,395	$ 225,735	$ 240,599	$ 231,462	$ 342,730		$ 216,975		$ 219,930		$ 226,066		$ 1,024,191	$ 1,005,701		$ 1,045,977
Depreciation and amortization expense													102,224	103,454
Stock-based compensation expense													13,683	43,613		18,380
Operating income (loss)	$ 108,037	$ 11,423	$ (38,443)	$ 3,623	$ 120,343	[1]	$ (9,353)	[1]	$ (26,572)	[1]	$ 136,712	[1]	84,640	221,130	[1]	127,948
Operating Segments [Member] | ACI On Premise [Member]
Segment Reporting Information [Line Items]
Revenues													598,590	591,252		589,006
Depreciation and amortization expense													13,094	14,581
Stock-based compensation expense													2,234	6,894
Operating income (loss)													331,766	290,713
Operating Segments [Member] | ACI On Demand [Member]
Segment Reporting Information [Line Items]
Revenues													425,601	399,033		362,368
Depreciation and amortization expense													34,171	29,385
Stock-based compensation expense													2,230	6,876
Operating income (loss)													(38,233)	(38,885)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues														15,416		$ 94,603
Depreciation and amortization expense													54,959	59,488
Stock-based compensation expense													9,219	29,843
Operating income (loss)													$ (208,893)	$ (30,698)

[1] The Company adopted ASU 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting, ("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.