Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Capitalized software development costs, net of accumulated amortization	$ 639,000	$ 484,000
Amortization of capitalized software development costs	300,000	230,000	$ 185,000
Capital expenditures, including internal-use software and website development	$ 749,348	787,041	$ 328,387
New Corporate Headquarters | Purchase and Sale Agreement
Property, Plant and Equipment [Line Items]
Capital expenditures, including internal-use software and website development		$ 229,000