Guarantor Financial Information - Schedule of Condensed Consolidated Balance Sheet Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 51,595	$ 57,059	$ 32,439	$ 116,227
Restricted cash	1,982	1,717
Accounts receivable, net of allowances for doubtful accounts	314,055	302,847
Unbilled services	206,527	179,036
Prepaid expenses and other current assets	39,040	38,225
Income tax receivable	1,589	1,363
Current deferred tax assets	7,460	7,512
Total current assets	622,248	587,759
Property and equipment, net	126,670	121,859
Goodwill	930,574	931,787
Intangible assets, net	391,209	417,824
Non-current deferred tax assets	3,952	3,944
Deferred financing costs and other assets	83,552	91,262
Total assets	2,158,205	2,154,435
Current liabilities:
Short-term borrowings, current portion of capital lease obligations and other financing arrangements	16,994	16,265
Accrued payroll, accounts payable and accrued expenses	289,766	286,613
Income taxes payable	1,313	1,209
Deferred revenue and client advances	227,484	199,130
Total current liabilities	535,557	503,217
Capital lease obligations, net of current portion	31,477	29,324
Long-term debt, net of current portion	2,103,373	2,071,232
Non-current income tax liability	6,926	6,461
Deferred tax liability	82,506	77,232
Other non-current liabilities	88,323	80,756
Total liabilities	2,848,162	2,768,222
Total inVentiv Health, Inc. stockholder's deficit	(691,209)	(615,181)
Noncontrolling interest	1,252	1,394
Total stockholder's deficit	(689,957)	(613,787)
Total liabilities and stockholder's deficit	2,158,205	2,154,435
Eliminations [Member]
Current assets:
Cash and cash equivalents	(92,408)	(52,037)	(77,065)	(35,244)
Intercompany receivables	(1,227,421)	(1,012,068)
Current deferred tax assets	(6,261)	(6,261)
Total current assets	(1,326,090)	(1,070,366)
Non-current intercompany receivables	(1,003,104)	(989,381)
Investment in consolidated subsidiaries	(783,809)	(775,458)
Total assets	(3,113,003)	(2,835,205)
Current liabilities:
Short-term borrowings, current portion of capital lease obligations and other financing arrangements	(87,482)	(52,037)
Accrued payroll, accounts payable and accrued expenses	(4,926)
Intercompany payables	(1,227,421)	(1,012,068)
Total current liabilities	(1,319,829)	(1,064,105)
Deferred tax liability	(6,261)	(6,261)
Non-current intercompany liabilities	(1,003,104)	(989,381)
Total liabilities	(2,329,194)	(2,059,747)
Total inVentiv Health, Inc. stockholder's deficit	(783,809)	(775,458)
Total stockholder's deficit	(783,809)	(775,458)
Total liabilities and stockholder's deficit	(3,113,003)	(2,835,205)
Inventiv Health Inc [Member]
Current assets:
Cash and cash equivalents	34,983	19,643	6,457	33,176
Restricted cash	825	569
Intercompany receivables	462,405	389,532
Prepaid expenses and other current assets	6,543	5,301
Current deferred tax assets	259	259
Total current assets	505,015	415,304
Property and equipment, net	23,392	21,665
Deferred financing costs and other assets	65,807	75,296
Non-current intercompany receivables	967,896	944,664
Investment in consolidated subsidiaries	697,821	689,216
Total assets	2,259,931	2,146,145
Current liabilities:
Short-term borrowings, current portion of capital lease obligations and other financing arrangements	209	4,006
Accrued payroll, accounts payable and accrued expenses	72,845	70,593
Intercompany payables	732,286	562,297
Income taxes payable		222
Total current liabilities	805,340	637,118
Long-term debt, net of current portion	2,103,373	2,071,232
Deferred tax liability	333	333
Other non-current liabilities	37,360	37,441
Non-current intercompany liabilities	4,734	15,202
Total liabilities	2,951,140	2,761,326
Total inVentiv Health, Inc. stockholder's deficit	(691,209)	(615,181)
Total stockholder's deficit	(691,209)	(615,181)
Total liabilities and stockholder's deficit	2,259,931	2,146,145
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents		3,439	5,141	19,838
Accounts receivable, net of allowances for doubtful accounts	252,296	236,884
Unbilled services	162,091	138,100
Intercompany receivables	687,314	557,758
Prepaid expenses and other current assets	11,476	12,181
Income tax receivable	587	310
Current deferred tax assets	12,198	12,198
Total current assets	1,125,962	960,870
Property and equipment, net	86,792	82,857
Goodwill	889,281	889,281
Intangible assets, net	384,350	410,059
Deferred financing costs and other assets	4,272	3,519
Non-current intercompany receivables	35,073	44,585
Investment in consolidated subsidiaries	85,988	86,242
Total assets	2,611,718	2,477,413
Current liabilities:
Short-term borrowings, current portion of capital lease obligations and other financing arrangements	16,619	14,025
Accrued payroll, accounts payable and accrued expenses	162,661	154,523
Intercompany payables	474,363	418,920
Income taxes payable	16
Deferred revenue and client advances	174,914	150,709
Total current liabilities	828,573	738,177
Capital lease obligations, net of current portion	31,423	29,126
Non-current income tax liability	5,543	5,360
Deferred tax liability	85,315	80,860
Other non-current liabilities	32,108	25,175
Non-current intercompany liabilities	968,031	944,796
Total liabilities	1,950,993	1,823,494
Total inVentiv Health, Inc. stockholder's deficit	660,725	653,919
Total stockholder's deficit	660,725	653,919
Total liabilities and stockholder's deficit	2,611,718	2,477,413
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	109,020	86,014	$ 97,906	$ 98,457
Restricted cash	1,157	1,148
Accounts receivable, net of allowances for doubtful accounts	61,759	65,963
Unbilled services	44,436	40,936
Intercompany receivables	77,702	64,778
Prepaid expenses and other current assets	21,021	20,743
Income tax receivable	1,002	1,053
Current deferred tax assets	1,264	1,316
Total current assets	317,361	281,951
Property and equipment, net	16,486	17,337
Goodwill	41,293	42,506
Intangible assets, net	6,859	7,765
Non-current deferred tax assets	3,952	3,944
Deferred financing costs and other assets	13,473	12,447
Non-current intercompany receivables	135	132
Total assets	399,559	366,082
Current liabilities:
Short-term borrowings, current portion of capital lease obligations and other financing arrangements	87,648	50,271
Accrued payroll, accounts payable and accrued expenses	59,186	61,497
Intercompany payables	20,772	30,851
Income taxes payable	1,297	987
Deferred revenue and client advances	52,570	48,421
Total current liabilities	221,473	192,027
Capital lease obligations, net of current portion	54	198
Non-current income tax liability	1,383	1,101
Deferred tax liability	3,119	2,300
Other non-current liabilities	18,855	18,140
Non-current intercompany liabilities	30,339	29,383
Total liabilities	275,223	243,149
Total inVentiv Health, Inc. stockholder's deficit	123,084	121,539
Noncontrolling interest	1,252	1,394
Total stockholder's deficit	124,336	122,933
Total liabilities and stockholder's deficit	$ 399,559	$ 366,082