CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Stockholders' Equity at Mar. 31, 2009	$ 525,367	$ 678	$ 386,224	$ 8,855	$ 203,936	$ (74,326)
Common Stock, Shares, Outstanding at Mar. 31, 2009		48,892,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	57,378				57,378
Foreign currency translation adjustments	1,047			1,047
Unrealized gain (loss) on hedges, net of tax	(3,630)			(3,630)
Comprehensive income	54,795
Exercise of stock options (shares)		1,493,000
Exercise of stock options	32,579	15	32,564
Issuance of restricted common stock (shares)		154,000
Issuance of restricted common stock	2	2
Repurchase of restricted common stock (shares)		(18,000)
Repurchase of restricted common stock	0	0
Cash dividends	(9,781)				(9,781)
Stock-based compensation	14,877		14,877
Income tax benefit associated with stock options	(476)		(476)
Repurchase of common stock (shares)		(1,935,000)
Repurchase of common stock	(49,652)					(49,652)
Sale of treasury stock (shares)		284,000
Sale of treasury stock	3,623		(4,782)			8,405
Retirement of treasury stock					(56,240)	56,240
Stockholders' Equity at Mar. 31, 2010	571,334	695	428,407	6,272	195,293	(59,333)
Common Stock, Shares, Outstanding at Mar. 31, 2010		48,870,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	109,243				109,243
Foreign currency translation adjustments	1,613			1,613
Unrealized gain (loss) on hedges, net of tax	(6,419)			(6,419)
Unrealized gain on investments, net of tax	7			7
Comprehensive income	104,444
Exercise of stock options (shares)		2,196,000
Exercise of stock options	50,106	22	50,084
Issuance of restricted common stock (shares)		424,000
Issuance of restricted common stock	3	3
Repurchase of restricted common stock (shares)		(26,000)
Repurchase of restricted common stock	0	0
Cash dividends	(9,703)				(9,703)
Stock-based compensation	15,873		15,873
Income tax benefit associated with stock options	4,319		4,319
Repurchase of common stock (shares)		(3,315,000)
Repurchase of common stock	(105,522)					(105,522)
Employees' tax withheld and paid for restricted stock and restricted stock units (shares)		(6,000)
Employees' tax withheld and paid for restricted stock and restricted stock units	(194)					(194)
Sale of treasury stock (shares)		172,000
Sale of treasury stock	4,192		344			3,848
Retirement of treasury stock					(102,365)	102,365
Stockholders' Equity at Mar. 31, 2011	634,852	720	499,027	1,473	192,468	(58,836)
Common Stock, Shares, Outstanding at Mar. 31, 2011		48,315,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	109,036				109,036
Foreign currency translation adjustments	(788)			(788)
Unrealized gain (loss) on hedges, net of tax	5,618			5,618
Unrealized gain on investments, net of tax	54			54
Comprehensive income	113,920
Exercise of stock options (shares)		1,831,000
Exercise of stock options	38,219	18	38,201
Issuance of restricted common stock (shares)		346,000
Issuance of restricted common stock	3	3
Repurchase of restricted common stock (shares)		(60,000)
Repurchase of restricted common stock	0	0
Cash dividends	(9,040)				(9,040)
Stock-based compensation	17,481		17,481
Income tax benefit associated with stock options	3,295		3,295
Repurchase of common stock (shares)		(8,027,000)
Repurchase of common stock	(273,791)					(273,791)
Employees' tax withheld and paid for restricted stock and restricted stock units (shares)		(75,000)
Employees' tax withheld and paid for restricted stock and restricted stock units	(2,596)					(2,596)
Sale of treasury stock (shares)		182,000
Sale of treasury stock	4,901		(786)			5,687
Retirement of treasury stock					(177,106)	177,106
Stockholders' Equity at Mar. 31, 2012	$ 527,244	$ 741	$ 557,218	$ 6,357	$ 115,358	$ (152,430)
Common Stock, Shares, Outstanding at Mar. 31, 2012		42,512,000