Schedule of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total revenue	$ 144,366	$ 142,351	$ 141,871	$ 130,569	$ 144,086	$ 152,883	$ 154,141	$ 143,489	$ 559,157	$ 594,599	$ 604,557
Cost of revenue									240,881	245,733	249,879
Operating expenses									175,776	151,240	151,281
Depreciation and amortization	1,997	2,179	2,235	2,202	2,197	2,275	2,326	2,262	8,613	9,060	9,090
Restructuring charge					(24)	(77)	3,022			2,921
Total costs and expenses	110,090	106,255	106,186	102,739	100,516	101,787	104,882	101,769	425,270	408,954	410,250
Operating income	34,276	36,096	35,685	27,830	43,570	51,096	49,259	41,720	133,887	185,645	194,307
Cloud Subscriptions
Segment Reporting Information [Line Items]
Total revenue	6,803	6,455	5,377	4,469	3,188	2,534	2,378	1,496	23,104	9,596	5,783
Software License
Segment Reporting Information [Line Items]
Total revenue	13,314	11,526	12,973	7,555	14,712	16,260	20,064	21,277	45,368	72,313	79,213
Cost of revenue	682	1,211	2,096	1,308	1,377	1,316	1,438	1,352	5,297	5,483	6,818
Maintenance
Segment Reporting Information [Line Items]
Total revenue	36,466	37,177	36,993	36,397	37,325	36,338	35,959	33,376	147,033	142,998	133,848
Services
Segment Reporting Information [Line Items]
Total revenue	84,525	84,136	82,267	78,757	77,183	84,211	85,327	79,781	329,685	326,502	351,785
Hardware
Segment Reporting Information [Line Items]
Total revenue	$ 3,258	$ 3,057	$ 4,261	$ 3,391	11,678	13,540	10,413	7,559	13,967	43,190	33,928
Cost of revenue					$ 8,416	$ 10,653	$ 7,766	$ 5,370		32,205	23,426
Americas
Segment Reporting Information [Line Items]
Total revenue									445,486	477,149	513,584
Cost of revenue									183,563	195,152	206,687
Operating expenses									156,793	134,167	133,637
Depreciation and amortization									7,601	8,324	8,313
Restructuring charge										2,813
Total costs and expenses									347,957	340,456	348,637
Operating income									97,529	136,693	164,947
Americas | Cloud Subscriptions
Segment Reporting Information [Line Items]
Total revenue									20,611	9,274	5,783
Americas | Software License
Segment Reporting Information [Line Items]
Total revenue									28,423	44,145	65,351
Americas | Maintenance
Segment Reporting Information [Line Items]
Total revenue									117,489	116,426	111,592
Americas | Services
Segment Reporting Information [Line Items]
Total revenue									265,165	264,186	296,983
Americas | Hardware
Segment Reporting Information [Line Items]
Total revenue									13,798	43,118	33,875
EMEA
Segment Reporting Information [Line Items]
Total revenue									84,744	85,349	66,282
Cost of revenue									43,080	36,124	30,711
Operating expenses									14,484	12,761	12,983
Depreciation and amortization									743	527	528
Restructuring charge										108
Total costs and expenses									58,307	49,520	44,222
Operating income									26,437	35,829	22,060
EMEA | Cloud Subscriptions
Segment Reporting Information [Line Items]
Total revenue									2,075	322
EMEA | Software License
Segment Reporting Information [Line Items]
Total revenue									11,406	22,875	9,187
EMEA | Maintenance
Segment Reporting Information [Line Items]
Total revenue									20,933	18,710	15,117
EMEA | Services
Segment Reporting Information [Line Items]
Total revenue									50,328	43,431	41,969
EMEA | Hardware
Segment Reporting Information [Line Items]
Total revenue									2	11	9
APAC
Segment Reporting Information [Line Items]
Total revenue									28,927	32,101	24,691
Cost of revenue									14,238	14,457	12,481
Operating expenses									4,499	4,312	4,661
Depreciation and amortization									269	209	249
Total costs and expenses									19,006	18,978	17,391
Operating income									9,921	13,123	7,300
APAC | Cloud Subscriptions
Segment Reporting Information [Line Items]
Total revenue									418
APAC | Software License
Segment Reporting Information [Line Items]
Total revenue									5,539	5,293	4,675
APAC | Maintenance
Segment Reporting Information [Line Items]
Total revenue									8,611	7,862	7,139
APAC | Services
Segment Reporting Information [Line Items]
Total revenue									14,192	18,885	12,833
APAC | Hardware
Segment Reporting Information [Line Items]
Total revenue									$ 167	$ 61	$ 44