Summary of Significant Accounting Policies - Additional Information (Detail)	2 Months Ended	12 Months Ended
	Jun. 08, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) Customer $ / shares shares	Mar. 31, 2016 USD ($) Customer $ / shares shares	Mar. 31, 2015 USD ($) Customer $ / shares shares
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of shares of common stock repurchased | shares		745,575	893,771	845,014
Treasury Stock, Value, Acquired, Cost Method		$ 27,999,000	$ 31,525,000	$ 31,798,000
Average price per share of common stock | $ / shares		$ 37.56	$ 35.27	$ 37.63
Maturities of short term investment interest-bearing securities		90 days
Accounts receivable due period		30 days
Unbilled account receivables		$ 14,579,000	$ 12,066,000
Capitalized software development costs		25,721,000	25,140,000
Accumulated amortization of software development costs		78,952,000	69,644,000
Impairment of goodwill, intangible assets or other long-lived assets		0
Goodwill		36,814,000	36,814,000
Accumulated amortization of goodwill		2,069,000	$ 2,069,000
ASU No. 2016-09 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Excess tax benefit		$ 500,000
Computer Software Property and Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Amortization period of computer software		5 years
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Maximum customer risk percentage		10.00%	10.00%	10.00%
Number of customer | Customer		0	0	0
Credit Concentration Risk [Member] | Accounts Receivable [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Maximum customer risk percentage		10.00%	10.00%
Number of customer | Customer		0	0
Private Equity Funds [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Investment		$ 2,250,000
Impairment recorded on investment		0	$ 0
Reduction to investments		284,000
Fair Value, Inputs, Level 2 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Transfer of assets		0
Fair Value, Inputs, Level 3 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Transfer of assets		$ 0
Subsequent Event [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of shares of common stock repurchased | shares	204,255
Treasury Stock, Value, Acquired, Cost Method	$ 9,100,000
Average price per share of common stock | $ / shares	$ 44.44