Fair Value Measurements (Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - Non Qualified Deferred Compensation Assets and Liabilities [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible and other long-term assets, net	$ 15,523	$ 15,013
Accounts payable	2,883	2,869
Other long-term liabilities	18,728	20,697
Investment in equity securities	18,684
Total debt		409,050
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible and other long-term assets, net	7,989
Investment in equity securities	18,684
Total debt		409,050
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Intangible and other long-term assets, net	7,534	15,013
Accounts payable	2,883	2,869
Other long-term liabilities	$ 18,728	$ 20,697