Long-Term Debt Payable to Banks - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Aug. 26, 2013	Aug. 25, 2013	Aug. 31, 2008
Line Of Credit Facility [Line Items]
Revolving credit facility	$ 0
Amortization of loan origination fees	11	19	150
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Unused borrowing commitment fee	0.125%
Revolving credit facility expiration date	Aug. 26, 2018
Line of Credit Facility, Commitment Fee Percentage	0.125%
Minimum borrowing capacity after dividend payment	5,000
Outstanding letters of credit	702
Revolving Credit Facility | Maximum
Line Of Credit Facility [Line Items]
Revolving credit facility	8,000
Revolving Credit Facility | Unsecured Debt
Line Of Credit Facility [Line Items]
Senior credit facility period	5 years
Senior credit facility				20,000
Line of credit, maximum borrowing capacity				35,000
Revolving Line of credit Description	accordion feature that may increase the amount to 2.5 times EBITDA
Option to convert Revolving Credit Facility, description	The Company has the option, subject to bank approval, during the five-year term of the Revolving Credit Facility, to convert the Facility to a secured credit facility which increases the borrowing limit to 3.5 times EBITDA (as defined in the Facility) up to a maximum of $35,000. As of March 31, 2015, the Company has not exercised this option
Line of credit, remaining borrowing capacity	19,298
Former Senior Credit Facility
Line Of Credit Facility [Line Items]
Senior credit facility					33,000
Former Senior Credit Facility | Line of Credit
Line Of Credit Facility [Line Items]
Senior credit facility					10,000
Unused borrowing commitment fee	0.375%
Former Senior Credit Facility | Term Loan
Line Of Credit Facility [Line Items]
Senior credit facility						$ 23,000