Fair Value Measurements - Levels of Inputs Used to Measure Fair Value of Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets designated for retirement and pension plans	$ 18,544	$ 18,164
Acquisition earnout accruals	6,197	12,033
Total fair value of assets	29,129	20,276
U.S. Non-Qualified Deferred Compensation Plan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	16,782	14,145
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fair value of assets	16,782	14,145
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Non-Qualified Deferred Compensation Plan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	16,782	14,145
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets designated for retirement and pension plans	18,544	18,164
Total fair value of assets	18,544	18,164
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition earnout accruals	6,197	12,033
Total fair value of assets	$ (6,197)	$ (12,033)