Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	$ 2,027	$ 1,470	$ 1,153
Charged (credited) to costs and expenses	7,462	8,357	7,139
Deductions	(7,777)	(7,800)	(6,822)
Ending Balance	1,712	2,027	1,470
Deferred Tax Asset Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning Balance	29,049	17,728	17,089
Charged (credited) to costs and expenses	4,450	11,321	639
Ending Balance	$ 33,499	$ 29,049	$ 17,728