Guarantor Financial Information - Schedule of Consolidating Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Income Statements, Captions [Line Items]
Net revenues	$ 521,410	$ 462,391	$ 1,461,804	$ 1,333,765
Reimbursed out-of-pocket expenses	87,931	62,460	238,331	182,815
Total revenues	609,341	524,851	1,700,135	1,516,580
Operating expenses:
Cost of revenues	336,753	302,389	946,320	869,359
Reimbursable out-of-pocket expenses	87,931	62,460	238,331	182,815
Selling, general and administrative expenses	140,738	140,853	424,375	425,189
Total operating expenses	565,422	505,702	1,609,026	1,477,363
Operating income (loss)	43,919	19,149	91,109	39,217
Loss on extinguishment of debt and refinancing costs		(10,062)		(10,062)
Interest income (expense), net	(57,294)	(54,988)	(170,877)	(160,672)
Other income	11,318		11,318
Income (loss) before income tax (provision) benefit and income (loss) from equity investments	(2,057)	(45,901)	(68,450)	(131,517)
Income tax (provision) benefit	(4,395)	(2,281)	(11,661)	(9,979)
Income (loss) before income (loss) from equity investments	(6,452)	(48,182)	(80,111)	(141,496)
Income (loss) from equity investments	2	(34)	(1,289)	(270)
Income (loss) from continuing operations	(6,450)	(48,216)	(81,400)	(141,766)
Net income (loss) from discontinued operations, net of tax				(8,163)
Net income (loss)	(6,450)	(48,216)	(81,400)	(149,929)
Less: Net (income) loss attributable to the noncontrolling interest	(238)	(9)	(604)	(529)
Net income (loss) attributable to inVentiv Health, Inc.	(6,688)	(48,225)	(82,004)	(150,458)
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Net revenues	(6,507)	(6,338)	(18,680)	(31,700)
Reimbursed out-of-pocket expenses	(104)	(30)	(242)	(271)
Total revenues	(6,611)	(6,368)	(18,922)	(31,971)
Operating expenses:
Cost of revenues	(5,896)	(5,929)	(17,043)	(30,027)
Reimbursable out-of-pocket expenses	(104)	(30)	(242)	(271)
Selling, general and administrative expenses	(611)	(409)	(1,637)	(1,673)
Total operating expenses	(6,611)	(6,368)	(18,922)	(31,971)
Income (loss) from equity investments	(38,384)	11,252	(48,273)	54,716
Income (loss) from continuing operations				54,716
Net income (loss)	(38,384)	11,252	(48,273)	54,716
Net income (loss) attributable to inVentiv Health, Inc.	(38,384)	11,252	(48,273)	54,716
Inventiv Health Inc [Member]
Operating expenses:
Selling, general and administrative expenses	22,866	13,892	59,444	31,693
Allocation of intercompany costs	(9,854)	(11,743)	(29,654)	(35,229)
Total operating expenses	13,012	2,149	29,790	(3,536)
Operating income (loss)	(13,012)	(2,149)	(29,790)	3,536
Loss on extinguishment of debt and refinancing costs		(3,570)		(3,570)
Interest income (expense), net	(44,994)	(42,273)	(134,399)	(122,959)
Other income	11,318		11,318
Intercompany interest income (expense)	12,342	10,767	35,265	31,265
Income (loss) before income tax (provision) benefit and income (loss) from equity investments	(34,346)	(37,225)	(117,606)	(91,728)
Income tax (provision) benefit				(127)
Income (loss) before income (loss) from equity investments	(34,346)	(37,225)	(117,606)	(91,855)
Income (loss) from equity investments	27,658	(11,000)	35,602	(58,603)
Income (loss) from continuing operations				(150,458)
Net income (loss)	(6,688)	(48,225)	(82,004)	(150,458)
Net income (loss) attributable to inVentiv Health, Inc.	(6,688)	(48,225)	(82,004)	(150,458)
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Net revenues	408,448	346,452	1,138,337	989,307
Reimbursed out-of-pocket expenses	77,745	49,283	205,811	143,347
Total revenues	486,193	395,735	1,344,148	1,132,654
Operating expenses:
Cost of revenues	271,754	228,411	750,784	656,655
Reimbursable out-of-pocket expenses	77,745	49,283	205,811	143,347
Selling, general and administrative expenses	88,264	89,727	266,007	282,328
Allocation of intercompany costs	7,886	8,960	23,765	26,853
Total operating expenses	445,649	376,381	1,246,367	1,109,183
Operating income (loss)	40,544	19,354	97,781	23,471
Loss on extinguishment of debt and refinancing costs		(6,492)		(6,492)
Interest income (expense), net	(12,445)	(12,759)	(36,892)	(38,000)
Intercompany interest income (expense)	(12,025)	(10,157)	(34,551)	(29,324)
Income (loss) before income tax (provision) benefit and income (loss) from equity investments	16,074	(10,054)	26,338	(50,345)
Income tax (provision) benefit	(1,488)	(893)	(6,113)	(6,584)
Income (loss) before income (loss) from equity investments	14,586	(10,947)	20,225	(56,929)
Income (loss) from equity investments	10,728	(286)	11,382	3,617
Income (loss) from continuing operations				(53,312)
Net income (loss) from discontinued operations, net of tax				(8,163)
Net income (loss)	25,314	(11,233)	31,607	(61,475)
Net income (loss) attributable to inVentiv Health, Inc.	25,314	(11,233)	31,607	(61,475)
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Net revenues	119,469	122,277	342,147	376,158
Reimbursed out-of-pocket expenses	10,290	13,207	32,762	39,739
Total revenues	129,759	135,484	374,909	415,897
Operating expenses:
Cost of revenues	70,895	79,907	212,579	242,731
Reimbursable out-of-pocket expenses	10,290	13,207	32,762	39,739
Selling, general and administrative expenses	30,219	37,643	100,561	112,841
Allocation of intercompany costs	1,968	2,783	5,889	8,376
Total operating expenses	113,372	133,540	351,791	403,687
Operating income (loss)	16,387	1,944	23,118	12,210
Interest income (expense), net	145	44	414	287
Intercompany interest income (expense)	(317)	(610)	(714)	(1,941)
Income (loss) before income tax (provision) benefit and income (loss) from equity investments	16,215	1,378	22,818	10,556
Income tax (provision) benefit	(2,907)	(1,388)	(5,548)	(3,268)
Income (loss) before income (loss) from equity investments	13,308	(10)	17,270	7,288
Income (loss) from continuing operations				7,288
Net income (loss)	13,308	(10)	17,270	7,288
Less: Net (income) loss attributable to the noncontrolling interest	(238)	(9)	(604)	(529)
Net income (loss) attributable to inVentiv Health, Inc.	$ 13,070	$ (19)	$ 16,666	$ 6,759