Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Deferred Compensation Arrangement with Individual Disclosure, Postretirement Benefits

The following table presents the Company’s (income) loss from investments held in employee deferred compensation trusts (in thousands):

	Year Ended December 31,
	2020		2019		2018
Dividend income	$	(8,322)	$	(10,425)	$	(10,857)
Realized and unrealized (gains) losses	(66,866)		(44,492)		22,343
	$	(75,188)	$	(54,917)	$	11,486

Schedule of Allocation of Plan Assets

The following table sets forth the composition of the underlying assets which comprise the Company’s deferred

compensation trust assets (in thousands):

	Fair Value Measurements Using
	Balance at December 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)	Significant Unobservable Inputs (Level 3)
Assets
Money market funds	$	69,681	$	69,681	—	—
Mutual funds - bond	27,282		27,282		—	—
Mutual funds - stock	234,667		234,667		—	—
Mutual funds - blend	75,004		75,004		—	—
	$	406,634	$	406,634	—	—
	Fair Value Measurements Using
	Balance at December 31, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)	Significant Unobservable Inputs (Level 3)
Assets
Money market funds	$	141,295	$	141,295	—	—
Mutual funds - bond	28,451		28,451		—	—
Mutual funds - stock	170,469		170,469		—	—
Mutual funds - blend	58,227		58,227		—	—
	$	398,442	$	398,442	—	—

Accounts Receivable, Allowance for Credit Loss

The following table sets forth the activity in the allowance for credit losses from December 31, 2019, through December 31, 2020 (in thousands):

	Allowance for Credit Losses
Balance as of December 31, 2019	$	22,885
Adoption of accounting pronouncement	558
Balance as of January 1, 2020	$	23,443
Charges to expense	4,200
Deductions	(7,906)
Other, including translation adjustments	(120)
Balance as of December 31, 2020	$	19,617

Depreciation Expense Computed Using Straight-Line Method over Useful Lives

Depreciation is computed using the straight-line method over the following useful lives:

Computer hardware	2 to 3 years
Computer software	2 to 3 years
Furniture and equipment	3 to 5 years
Leasehold improvements	Term of lease

Property and equipment consisted of the following (in thousands):

	December 31,
	2020		2019
Computer hardware	$	159,180	$	164,547
Computer software	250,585		291,681
Furniture and equipment	91,112		88,136
Leasehold improvements	164,807		150,644
Property and equipment, cost	665,684		695,008
Accumulated depreciation	(555,867)		(566,623)
Property and equipment, net	$	109,817	$	128,385