Fair value measurements - Roll-Forward of Fair Value of the Company's Contingent Consideration Obligations (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
|
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Changes in fair value | $ 1,013 | $ 215 |
Significant unobservable inputs (Level 3) [Member] | Contingent consideration obligations [Member] | ||
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Beginning balance | 8,665 | |
Changes in fair value | 1,013 | |
Ending balance | $ 9,678 |