Statement of Stockholders' Equity (USD $) In Thousands	Total	Common Stock and Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Mar. 31, 2012	$ 254,107	$ 198,661	$ (56,838)	$ 110,194	$ 2,090
Beginning balance, shares at Mar. 31, 2012		37,806	6,482
Net income (loss)	7,648			7,648
Other comprehensive income (loss)	(5,183)				(5,183)
Stock-based compensation	3,451	3,451
Proceeds from sale of shares through employee equity incentive plans, related excess tax benefits and others	865	865
Proceeds from sale of shares through employee equity incentive plans, related excess tax benefits and others, shares		115
Purchase of treasury stock	(6,505)		(6,505)
Purchase of treasury stock, shares			707
Re-issurance of treasury stock under stock compensation plans	1,079		1,349	(270)
Re-issuance of treasury stock under stock compensation plans, shares			(153)
Dividend	(1,854)			(1,854)
Balance at Mar. 31, 2013	253,608	202,977	(61,994)	115,718	(3,093)
Ending balance, shares at Mar. 31, 2013		37,921	7,036
Net income (loss)	6,046			6,046
Other comprehensive income (loss)	8,122				8,122
Stock-based compensation	2,785	2,785
Proceeds from sale of shares through employee equity incentive plans, related excess tax benefits and others	908	908
Proceeds from sale of shares through employee equity incentive plans, related excess tax benefits and others, shares		96
Purchase of treasury stock	(602)		(602)
Purchase of treasury stock, shares			60
Re-issurance of treasury stock under stock compensation plans	3,509		3,814	(305)
Re-issuance of treasury stock under stock compensation plans, shares			(433)
Dividend	(3,744)			(3,744)
Balance at Mar. 31, 2014	270,632	206,670	(58,782)	117,715	5,029
Ending balance, shares at Mar. 31, 2014		38,017	6,663
Net income (loss)	23,740			23,740
Other comprehensive income (loss)	(28,117)				(28,117)
Stock-based compensation	2,867	2,867
Proceeds from sale of shares through employee equity incentive plans, related excess tax benefits and others	551	551
Proceeds from sale of shares through employee equity incentive plans, related excess tax benefits and others, shares		100
Re-issurance of treasury stock under stock compensation plans	1,891		1,949	(58)
Re-issuance of treasury stock under stock compensation plans, shares			(221)
Dividend	(4,263)			(4,263)
Balance at Mar. 31, 2015	$ 267,301	$ 210,088	$ (56,833)	$ 137,134	$ (23,088)
Ending balance, shares at Mar. 31, 2015		38,117	6,442