Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Apr. 30, 2021	Dec. 31, 2020
Other Significant Noncash Transactions [Line Items]
Deferred compensation plan	$ 37,894		$ 34,501
Supplemental executive retirement plan	19,965	$ 20,000	20,628
Operating lease liabilities	14,067		14,692
Interest rate swap derivative instruments	503		1,774
Other long-term liabilities	19,323		19,353
Total Other long-term liabilities	91,752		90,948
Deferred Payroll Taxes | COVID-19
Other Significant Noncash Transactions [Line Items]
Payroll tax payments deferred by CARES Act	$ 19,300		$ 19,300