Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite Lived Intangible Assets [Line Items]
Impairment of intangible assets			$ 20,677
Indefinite-lived intangible assets			6,100
Amortization of acquired intangible assets			$ 29,000	$ 27,400	$ 24,600
Developed Technology [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-average remaining useful lives of acquired intangible assets			2 years 4 months 24 days
Developed Technology [Member] | Rising Tide [Member]
Finite Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 18,200	$ 18,200
Developed Technology [Member] | Zindagi [Member]
Finite Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 2,400	$ 2,400
Trademarks, Branding and Domain Names [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-average remaining useful lives of acquired intangible assets			2 months 12 days
Acquired Lease Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Weighted-average remaining useful lives of acquired intangible assets			3 years 3 months 18 days