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Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Retirement Benefits [Abstract]
Percentage of common stock matched under deferred compensation plan	50.00%
First certain percentage of eligible contribution under deferred compensation plan	6.00%
Recorded expense under deferred compensation plan	$ 0.4	$ 0.4	$ 0.4

X

- Definition

Defined Contribution Plan Company Contribution Percentage Match Common Stock

+ References

No definition available.

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X

- Definition

Defined Contribution Plan Percentage Of First Eligible Employee Contribution Matched By Employer

+ References

No definition available.

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X

- References

No definition available.

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X

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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