Summary of Significant Accounting Policies - Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income	$ 9,664	$ 9,768	$ 17,825	$ 18,290
Denominator:
Weighted average shares outstanding for basic net income per common share (in shares)	9,037	9,331	9,175	9,321
Effect of dilutive stock options (in shares)	89	89	96	82
Adjusted weighted average share outstanding for diluted net income per common share (in shares)	9,126	9,420	9,271	9,403
Basic net income per common share (in dollars per share)	$ 1.07	$ 1.05	$ 1.94	$ 1.96
Diluted net income per common share (in dollars per share)	$ 1.06	$ 1.04	$ 1.92	$ 1.95