Nature of Business and Summary of Significant Accounting Policies - Revenues in Condensed Consolidated Statements of Operations from Arrangements for which Vendor-Specific Objective Evidence of Fair Value Does Not Exist for Each Undelivered Element (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue Recognition, Milestone Method [Line Items]
License	$ 159,277	$ 43,256	$ 33,510	$ 37,423	$ 94,230	$ 50,237	$ 67,161	$ 39,577	$ 273,466	$ 251,205	$ 235,157
Maintenance	58,072	57,741	60,332	57,331	63,000	59,262	60,141	59,492	233,476	241,895	255,993
Services	24,262	19,809	23,823	19,576	34,371	25,842	23,110	23,497	87,470	106,820	105,584
Total revenues	$ 342,730	$ 216,975	$ 219,930	$ 226,066	$ 308,637	$ 238,701	$ 265,822	$ 232,817	1,005,701	1,045,977	1,016,149
Vendor Specific Objective Evidence of Fair Value [Member]
Revenue Recognition, Milestone Method [Line Items]
License									6,759	7,797	22,211
Maintenance									3,268	3,801	7,699
Services									268	321	13
Total revenues									$ 10,295	$ 11,919	$ 29,923