Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Apr. 30, 2021	Dec. 31, 2020
Other Significant Noncash Transactions [Line Items]
Deferred compensation plan	$ 38,749		$ 34,501
Supplemental executive retirement plan	0	$ 20,000	20,628
Operating lease liabilities	12,712		14,692
Interest rate swap derivative instruments	296		1,774
Other long-term liabilities	19,321		19,353
Total Other long-term liabilities	$ 71,078		90,948
Operating lease liabilities, financial statement location	Total Other long-term liabilities
Deferred Payroll Taxes | COVID-19
Other Significant Noncash Transactions [Line Items]
Other long-term liabilities	$ 19,300		$ 19,300