Fair Value Measurements - Change in Redeemable Noncontrolling Interests (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Redeemable Noncontrolling Interests [Roll Forward]
Balance at beginning of period	$ 28,885	$ 26,564
Initial redeemable noncontrolling interest related to business combinations		4,997
Net loss attributable to redeemable noncontrolling interests	(316)	(4,513)
Adjustment of the redeemable noncontrolling interests to fair value	1,323	5,730
Effect of foreign currency translation attributable to redeemable noncontrolling interests	(2,958)	(3,893)
Balance at end of period	$ 26,934	$ 28,885