Financial Instruments - Carrying And Estimated Fair Value Of Other Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	$ 15,184	$ 14,826
Long-term debt	278,193	275,609
Total	293,377	290,435
Level 1 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	0	0
Long-term debt	0	0
Total	0	0
Level 2 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	0	0
Long-term debt	417,937	398,016
Total	417,937	398,016
Level 3 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	15,184	14,826
Long-term debt	0	0
Total	$ 15,184	$ 14,826