Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Advertising costs for the years ended December 31, 2018, 2017 and 2016, are reflected in the following table (in thousands):



	Years Ended December 31,
	2018		2017		2016
Advertising Costs	$	52,499	$	49,433	$	47,312

Depreciation Expense Computed Using Straight-Line Method over Useful Lives

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



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

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



	December 31,
	2018			2017
Computer hardware	$	177,237		$	171,515
Computer software	378,734			376,761
Furniture and equipment	107,421			102,424
Leasehold improvements	160,521			148,764
Other	10,319			9,907
Property and equipment, cost	834,232			809,371
Accumulated depreciation	(709,056		)	(664,484		)
Property and equipment, net	$	125,176		$	144,887

Internal-Use Software Development Costs Capitalized

Internal-use software development costs capitalized for the years ended December 31, 2018, 2017 and 2016, are reflected in the following table (in thousands):



	Years Ended December 31,
	2018		2017		2016
Internal-use software development costs	$	3,287	$	9,030	$	33,753