Financial Instruments - Carrying And Estimated Fair Value Of Other Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration, including current portion	$ 18,545	$ 14,826
Long-term debt	283,454	275,609
Total	301,999	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	394,079	398,016
Total	394,079	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	18,545	14,826
Long-term debt	0	0
Total	$ 18,545	$ 14,826