Property and Equipment - Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Capitalized internal use software development costs	$ 29,700	$ 25,300	$ 21,500
Property and Equipment
Total property and equipment	222,404
Less: accumulated depreciation and amortization	(81,148)
Total property and equipment, net	141,256
Total property and equipment		108,270
Less: accumulated depreciation and amortization		(44,736)
Total property and equipment, net		63,534
Capitalized internal-use software development costs
Property and Equipment
Total property and equipment	100,155
Total property and equipment		72,647
Data center equipment
Property and Equipment
Total property and equipment	22,009
Total property and equipment		0
Leasehold improvements
Property and Equipment
Total property and equipment	55,886
Total property and equipment		15,293
Office equipment
Property and Equipment
Total property and equipment	25,083
Total property and equipment		13,563
Furniture and fixtures
Property and Equipment
Total property and equipment	10,095
Total property and equipment		4,918
Software
Property and Equipment
Total property and equipment	$ 9,176
Total property and equipment		$ 1,849