Income Taxes - Reconciliation of income tax provision computed at the U.S. federal statutory tax rates to income tax expense (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Income Tax Disclosure [Abstract]
Income taxes at U.S. statutory rates	$ 9,940	$ 9,557	$ 9,230
State income taxes, net of federal tax benefit	583	562	540
Permanent differences	(35)	(74)	(68)
Other	(61)	96	10
Total provision for income taxes	$ 10,427	$ 10,141	$ 9,712