Net Income Per Share - Reconciliation of the numerators and denominators of the basic and diluted net income per share computations (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Net income (numerator):
Net income	$ 4,973	$ 4,755
Shares (denominator):
Weighted average number of common shares outstanding used in basic computation	19,961	19,848
Common shares issuable upon vesting of restricted stock	121	146
Common shares issuable upon conversion of preferred shares	10	10
Shares used in diluted computation	20,092	20,004
Net income per common share:
Basic (in dollars per share)	$ 0.25	$ 0.24
Diluted (in dollars per share)	$ 0.25	$ 0.24