Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Composition of property and equipment

The composition of property and equipment as of December 31, 2019 and 2020 is as follows (in thousands):

	December 31, 2019		December 31, 2020		Estimated useful life (years)
Land	$	7,138	$	7,138	—
Buildings and improvements	21,143		21,373		5-40
Furniture and office equipment	73,457		77,337		5-7
Computer hardware	10,173		15,684		3-7
Computer software	137,150		183,015		3-10
Leasehold improvements	49,241		65,719		3-10
Construction in progress	7,808		15,517		—
	306,110		385,783
Accumulated depreciation and amortization	(189,081)		(226,929)
	$	117,029	$	158,854