Fair Value Measurements - Summary of Changes in the Fair Value of Level 3 Contingent Consideration (Parenthetical) (Detail) - Level 3 [Member] - Contingent Consideration [Member] - FeedbackNow [Member]	Sep. 30, 2019
Discount Rate [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of contingent consideration discount rate	17.3
Revenue Volatility [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value of contingent consideration discount rate	26.6