Fair Value Measurements - Changes in Estimated Fair Value of Contingent Consideration Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value of acquisition contingencies	$ 0	$ 0	$ 42
Balance at December 31, 2014		5,608		$ 5,756
Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014		5,608		5,756
Cash payments		(129)
Unrealized gain on foreign currency translation		(19)
Balance at June 30, 2015		5,608
Commitments [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014		5,608		5,756
Commitments [Member] | Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014		$ 5,608		$ 5,756