Fair Value Measurements - Changes in Estimated Fair Value of Contingent Consideration Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013	$ 6,719	$ 8,808
Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013	6,719	8,808
Cash payments	(2,112)
Losses recorded for fair value adjustments	42
Unrealized gain on foreign currency translation	(19)
Balance at September 30, 2014	6,719
Commitments [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013	6,719	8,808
Commitments [Member] | Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013	$ 6,719	$ 8,808