Fair Value Measurements - Change in Redeemable Noncontrolling Interests (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Redeemable Noncontrolling Interests [Roll Forward]
Balance at beginning of period	$ 45,755	$ 38,624
Addition to redeemable noncontrolling interest	277	826
Redemption of redeemable noncontrolling interest		(3,562)
Net loss attributable to redeemable noncontrolling interest	(6,928)	(47,831)
Adjustment of the redeemable noncontrolling interest to fair value	85,139	74,194
Effect of foreign currency translation attributable to redeemable noncontrolling interest	1,972	(16,496)
Balance at end of period	$ 126,215	$ 45,755