Goodwill and Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	$ 2,453	$ 3,260
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Other acquired intangible assets estimated useful lives	2 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Other acquired intangible assets estimated useful lives	10 years