Summary of Significant Accounting Policies - Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net income	$ 6,992	$ 11,229	$ 3,706	$ 8,161
Denominator:
Weighted average shares outstanding for basic net income per common share (in shares)	9,076	9,148	9,065	9,245
Effect of dilutive stock options (in shares)	31	89	46	100
Adjusted weighted average shares outstanding for diluted net income per common share (in shares)	9,107	9,237	9,111	9,345
Basic net income per common share (in dollars per share)	$ 0.77	$ 1.23	$ 0.41	$ 0.88
Diluted net income per common share (in dollars per share)	$ 0.77	$ 1.22	$ 0.41	$ 0.87