Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Treasury Stock	Retained Earnings	Total
Balance at Mar. 31, 2014	$ 31,152		$ 110,786	$ 141,938
Balance (in shares) at Mar. 31, 2014	12,221
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			16,856	16,856
Issuance of common stock under stock options	$ 389			389
Issuance of common stock under stock options (in shares)	151
Grants of restricted share awards, net of forfeitures (in shares)	44
Excess tax benefit on share awards	$ 600			600
Share-based compensation	$ 514			514
Common shares purchased		$ (70,409)		(70,409)
Common shares purchased (in shares)	(4,714)
Balance at Mar. 31, 2015	$ 32,655	(70,409)	127,642	89,888
Balance (in shares) at Mar. 31, 2015	7,702
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			12,379	12,379
Issuance of common stock under stock options	$ 85			85
Issuance of common stock under stock options (in shares)	13
Grants of restricted share awards, net of forfeitures (in shares)	38
Tax deficiency on share awards	$ (38)			(38)
Excess tax benefit on share awards	11			11
Share-based compensation	574			574
Additional tender offer cost		(50)		(50)
Balance at Mar. 31, 2016	$ 33,287	(70,459)	140,021	102,849
Balance (in shares) at Mar. 31, 2016	7,753
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			5,409	5,409
Issuance of common stock under stock options	$ 50			50
Issuance of common stock under stock options (in shares)	9
Grants of restricted share awards, net of forfeitures (in shares)	48
Tax deficiency on share awards	$ (66)			(66)
Excess tax benefit on share awards	11			11
Share-based compensation	607			607
Balance at Mar. 31, 2017	$ 33,889	$ (70,459)	$ 145,430	$ 108,860
Balance (in shares) at Mar. 31, 2017	7,810