Supplemental Guarantor Financial Statements - Condensed Consolidating Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Condensed Financial Statements Captions [Line Items]
Cash and cash equivalents	$ 74,077		$ 64,057
Accounts receivable, net	264,076		243,900
Contract asset	11,942
Prepaid expenses and other current assets	35,559		38,742
Prepaid income taxes			12,166
Restricted cash	543		592
Net property, plant and equipment	101,994		100,956
Deferred income taxes, long-term	2,041		2,324
Long-term contract asset	22,076
Goodwill, intangible and other assets, net	5,037,276		5,076,779
Total assets	5,549,584		5,539,516
Current portion of long-term debt	37,338		37,863
Accounts payable	17,637		27,087
Accrued expenses	110,688		168,078
Income taxes payable	16,182		6,031
Deferred revenue	193,024		204,601
Long-term debt, net of current portion	1,949,232		2,007,332
Other long-term liabilities	120,621		118,679
Deferred income taxes, long-term	288,954		283,457
Total liabilities	2,733,676		2,853,128
Total stockholders’ equity	2,815,908		2,686,388
Total liabilities and stockholders’ equity	5,549,584		5,539,516
Revenues	421,929	$ 407,699
Cost of revenues	229,580	217,459
Gross profit	192,349	190,240
Operating expenses:
Selling and marketing	31,150	30,242
Research and development	38,919	38,449
General and administrative	35,433	31,832
Total operating expenses	105,502	100,523
Operating income	86,847	89,717
Interest expense, net	(25,354)	(29,020)
Other (expense) income, net	438	(71)
Loss on extinguishment of debt		(2,326)
Income before income taxes	61,931	58,300
Provision for income taxes	10,681	10,153
Net income	51,250	48,147
Other comprehensive income, net of tax:
Foreign currency exchange translation adjustment	5,217	10,779
Comprehensive income	56,467	58,926
Cash Flow from Operating Activities:
Net income	51,250	48,147
Non-cash adjustments	64,347	68,308
Changes in operating assets and liabilities	(45,653)	(58,567)
Net cash provided by operating activities	69,944	57,888
Cash Flow from Investment Activities:
Additions to property and equipment	(7,163)	(5,990)
Cash paid for business acquisitions, net of cash acquired	(191)	1,805
Additions to capitalized software	(3,945)	(3,277)
Net cash used in investing activities	(11,299)	(7,462)
Cash Flow from Financing Activities:
Cash received from debt borrowings	45,000	45,000
Repayments of debt	(106,250)	(105,200)
Transactions involving Holding's common stock	12,457	713
Fees paid for debt extinguishment		(1,363)
Net cash used in financing activities	(48,793)	(60,850)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	119	1,663
Net increase (decrease) in cash, cash equivalents and restricted cash	9,971	(8,761)
Cash, cash equivalents and restricted cash, beginning of period	64,649	119,674
Cash, cash equivalents and restricted cash, end of period	74,620	110,913
Parent Company [Member]
Condensed Financial Statements Captions [Line Items]
Investment in subsidiaries	3,512,062		3,373,730
Total assets	3,512,062		3,373,730
Accrued expenses	7,344		16,157
Long-term debt, net of current portion	600,000		600,000
Intercompany payables	88,810		71,185
Total liabilities	696,154		687,342
Total stockholders’ equity	2,815,908		2,686,388
Total liabilities and stockholders’ equity	3,512,062		3,373,730
Operating expenses:
Interest expense, net	(8,813)	(8,813)
Earnings from subsidiaries	60,063	56,960
Income before income taxes	51,250	48,147
Net income	51,250	48,147
Other comprehensive income, net of tax:
Foreign currency exchange translation adjustment	5,217	10,779
Comprehensive income	56,467	58,926
Cash Flow from Operating Activities:
Net income	51,250	48,147
Intercompany transactions	17,626	17,625
Earnings from subsidiaries	(60,063)	(56,960)
Changes in operating assets and liabilities	(8,813)	(8,812)
Guarantor Subsidiaries [Member]
Condensed Financial Statements Captions [Line Items]
Cash and cash equivalents	10,952		21,191
Accounts receivable, net	177,378		173,997
Contract asset	11,156
Prepaid expenses and other current assets	16,100		19,770
Prepaid income taxes			6,366
Restricted cash	543		592
Net property, plant and equipment	61,058		60,774
Investment in subsidiaries	982,351		938,794
Intercompany receivables	265,532		199,503
Long-term contract asset	21,406
Goodwill, intangible and other assets, net	3,836,385		3,871,503
Total assets	5,382,861		5,292,490
Current portion of long-term debt	12,199		12,626
Accounts payable	8,441		19,223
Accrued expenses	57,597		96,540
Income taxes payable	13,140
Deferred revenue	163,056		182,181
Long-term debt, net of current portion	1,154,848		1,197,576
Other long-term liabilities	83,125		82,239
Intercompany payables	116,137		74,005
Deferred income taxes, long-term	262,256		254,370
Total liabilities	1,870,799		1,918,760
Total stockholders’ equity	3,512,062		3,373,730
Total liabilities and stockholders’ equity	5,382,861		5,292,490
Revenues	287,651	286,034
Cost of revenues	149,678	144,757
Gross profit	137,973	141,277
Operating expenses:
Selling and marketing	22,025	22,625
Research and development	27,289	27,169
General and administrative	26,690	22,608
Total operating expenses	76,004	72,402
Operating income	61,969	68,875
Interest expense, net	(12,267)	(15,004)
Other (expense) income, net	(18,846)	(17,731)
Loss on extinguishment of debt		(1,743)
Earnings from subsidiaries	33,480	28,629
Income before income taxes	64,336	63,026
Provision for income taxes	4,273	6,066
Net income	60,063	56,960
Other comprehensive income, net of tax:
Foreign currency exchange translation adjustment	5,217	10,779
Comprehensive income	65,280	67,739
Cash Flow from Operating Activities:
Net income	60,063	56,960
Non-cash adjustments	48,163	51,401
Intercompany transactions	(22,927)	(12,791)
Earnings from subsidiaries	(33,480)	(28,629)
Changes in operating assets and liabilities	(22,644)	(36,492)
Net cash provided by operating activities	29,175	30,449
Cash Flow from Investment Activities:
Additions to property and equipment	(4,173)	(5,027)
Cash paid for business acquisitions, net of cash acquired		1,802
Additions to capitalized software	(2,689)	(2,331)
Net cash used in investing activities	(6,862)	(5,556)
Cash Flow from Financing Activities:
Cash received from debt borrowings	45,000	45,000
Repayments of debt	(90,250)	(77,200)
Transactions involving Holding's common stock	12,457	713
Fees paid for debt extinguishment		(943)
Intercompany transactions	192	60
Net cash used in financing activities	(32,601)	(32,370)
Net increase (decrease) in cash, cash equivalents and restricted cash	(10,288)	(7,477)
Cash, cash equivalents and restricted cash, beginning of period	21,783	35,511
Cash, cash equivalents and restricted cash, end of period	11,495	28,034
Non-guarantor Subsidiaries [Member]
Condensed Financial Statements Captions [Line Items]
Cash and cash equivalents	63,125		42,866
Accounts receivable, net	86,698		69,903
Contract asset	786
Prepaid expenses and other current assets	19,459		18,972
Prepaid income taxes			5,800
Net property, plant and equipment	40,936		40,182
Intercompany receivables	116,137		74,005
Deferred income taxes, long-term	2,041		2,324
Long-term contract asset	670
Goodwill, intangible and other assets, net	1,200,891		1,205,276
Total assets	1,530,743		1,459,328
Current portion of long-term debt	25,139		25,237
Accounts payable	9,196		7,864
Accrued expenses	45,747		55,381
Income taxes payable	3,042		6,031
Deferred revenue	29,968		22,420
Long-term debt, net of current portion	194,384		209,756
Other long-term liabilities	37,496		36,440
Intercompany payables	176,722		128,318
Deferred income taxes, long-term	26,698		29,087
Total liabilities	548,392		520,534
Total stockholders’ equity	982,351		938,794
Total liabilities and stockholders’ equity	1,530,743		1,459,328
Revenues	134,453	122,100
Cost of revenues	80,077	73,137
Gross profit	54,376	48,963
Operating expenses:
Selling and marketing	9,125	7,617
Research and development	11,630	11,280
General and administrative	8,743	9,224
Total operating expenses	29,498	28,121
Operating income	24,878	20,842
Interest expense, net	(4,274)	(5,203)
Other (expense) income, net	19,284	17,660
Loss on extinguishment of debt		(583)
Income before income taxes	39,888	32,716
Provision for income taxes	6,408	4,087
Net income	33,480	28,629
Other comprehensive income, net of tax:
Foreign currency exchange translation adjustment	7,386	10,109
Comprehensive income	40,866	38,738
Cash Flow from Operating Activities:
Net income	33,480	28,629
Non-cash adjustments	16,184	16,907
Intercompany transactions	5,301	(4,834)
Changes in operating assets and liabilities	(14,196)	(13,263)
Net cash provided by operating activities	40,769	27,439
Cash Flow from Investment Activities:
Additions to property and equipment	(2,990)	(963)
Cash paid for business acquisitions, net of cash acquired	(191)	3
Additions to capitalized software	(1,256)	(946)
Net cash used in investing activities	(4,437)	(1,906)
Cash Flow from Financing Activities:
Repayments of debt	(16,000)	(28,000)
Fees paid for debt extinguishment		(420)
Intercompany transactions	(192)	(60)
Net cash used in financing activities	(16,192)	(28,480)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	119	1,663
Net increase (decrease) in cash, cash equivalents and restricted cash	20,259	(1,284)
Cash, cash equivalents and restricted cash, beginning of period	42,866	84,163
Cash, cash equivalents and restricted cash, end of period	63,125	82,879
Consolidation, Eliminations [Member]
Condensed Financial Statements Captions [Line Items]
Investment in subsidiaries	(4,494,413)		(4,312,524)
Intercompany receivables	(381,669)		(273,508)
Total assets	(4,876,082)		(4,586,032)
Intercompany payables	(381,669)		(273,508)
Total liabilities	(381,669)		(273,508)
Total stockholders’ equity	(4,494,413)		(4,312,524)
Total liabilities and stockholders’ equity	(4,876,082)		$ (4,586,032)
Revenues	(175)	(435)
Cost of revenues	(175)	(435)
Operating expenses:
Earnings from subsidiaries	(93,543)	(85,589)
Income before income taxes	(93,543)	(85,589)
Net income	(93,543)	(85,589)
Other comprehensive income, net of tax:
Foreign currency exchange translation adjustment	(12,603)	(20,888)
Comprehensive income	(106,146)	(106,477)
Cash Flow from Operating Activities:
Net income	(93,543)	(85,589)
Earnings from subsidiaries	$ 93,543	$ 85,589