Long-Term Debt Payable to Banks - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified			6 Months Ended		6 Months Ended
	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2014 Revolving Credit Facility	Sep. 30, 2014 Revolving Credit Facility Maximum	Sep. 30, 2014 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
Borrowing capacity ratio, maximum					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 September 30, 2014, the Company has not exercised this option.
Unused borrowing commitment fee			0.125%
Revolving credit facility expiration date			Aug. 26, 2018
Revolving credit facility	0	0	0	8,000
Line of Credit Facility, Commitment Fee Percentage			0.125%
Minimum borrowing capacity after dividend payment			5,000
Outstanding letters of credit			202
Line of credit, remaining borrowing capacity					$ 19,798