Financial Instruments - Carrying And Estimated Fair Value Of Other Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	$ 14,826	$ 3,698
Long-term debt	275,609	265,571
Total	290,435	269,269
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	398,016	291,837
Total	398,016	291,837
Level 3 | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	14,826	3,698
Long-term debt	0	0
Total	$ 14,826	$ 3,698