CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 91,298	$ 84,947	$ 200,324	$ 171,378
Comprehensive income adjustments:
Unrealized gains (losses) on available-for-sale securities, net of income taxes of $49, $9, ($7) and ($95)	79	14	(11)	(151)
Unrealized (losses) gains on derivative instruments, net of income taxes of ($3,125), $327, ($7,462) and ($713)	(10,343)	3,444	(19,268)	(220)
Defined benefit plan adjustments, net of income taxes of $71			184
Foreign currency translation, net of income taxes of ($3,955), $146, ($4,803) and ($2,665)	(31,255)	13,007	(23,537)	(17,005)
Reclassification adjustments:
Losses on derivative instruments included in net income, net of income taxes of $650, $1,590, $2,431 and $3,246	2,941	3,502	7,501	7,338
Amortization of actuarial losses included in net income, net of income taxes of $78, $85, $151 and $168	145	147	281	287
Comprehensive income	52,865	105,061	165,474	161,627
Comprehensive loss (income) attributable to non-controlling interests	558	1	225	(29)
Comprehensive income attributable to Quintiles Transnational Holdings Inc.	$ 53,423	$ 105,062	$ 165,699	$ 161,598