Summary of Significant Accounting Policies - Composition of Underlying Assets Comprising Company's Deferred Compensation Plans Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	$ 406,634	$ 398,442
Quoted Prices in Active Markets for Identical Assets (Level 1)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	406,634	398,442
Significant Other Observable Inputs (Level 2)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Significant Unobservable Inputs (Level 3)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Money market funds
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	69,681	141,295
Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	69,681	141,295
Money market funds | Significant Other Observable Inputs (Level 2)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Money market funds | Significant Unobservable Inputs (Level 3)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Mutual funds - bond
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	27,282	28,451
Mutual funds - bond | Quoted Prices in Active Markets for Identical Assets (Level 1)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	27,282	28,451
Mutual funds - bond | Significant Other Observable Inputs (Level 2)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Mutual funds - bond | Significant Unobservable Inputs (Level 3)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Mutual funds - stock
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	234,667	170,469
Mutual funds - stock | Quoted Prices in Active Markets for Identical Assets (Level 1)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	234,667	170,469
Mutual funds - stock | Significant Other Observable Inputs (Level 2)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Mutual funds - stock | Significant Unobservable Inputs (Level 3)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Mutual funds - blend
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	75,004	58,227
Mutual funds - blend | Quoted Prices in Active Markets for Identical Assets (Level 1)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	75,004	58,227
Mutual funds - blend | Significant Other Observable Inputs (Level 2)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	0	0
Mutual funds - blend | Significant Unobservable Inputs (Level 3)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Plan Assets, Current	$ 0	$ 0