Consolidated Statements of Stockholders' Equity and Comprehensive Income (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Retained Earnings (Accumulated Deficit)	Stockholders' Equity, Total [Member]
Balances at Dec. 31, 2009		$ 455	$ 1,284,140	$ 140,470	$ (660,658)	$ 764,407
Balances (in shares) at Dec. 31, 2009		454,586
Comprehensive income (loss):
Net income	423,075					423,075
Actuarial losses related to defined benefit pension plans	(788)			(788)		(788)
Unrealized losses on investments, net of tax				(2,102)		(2,102)
Inclusion of foreign CTA adjustments in net income	(99,779)			(99,779)		(99,779)
Foreign currency translation adjustments (CTA)	(21,472)			(21,472)		(21,472)
Total comprehensive income	298,934					298,934
Stock-based compensation expense			58,487			58,487
Tax benefit on stock-based compensation expense			1,664			1,664
Exercise of stock options		5	22,493			22,498
Exercise of stock options (in shares)		5,344
Issuance of commons stock under employee stock purchase plan		2	7,411			7,413
Issuance of common stock under employee stock purchase plan (in shares)		2,028
Vested restricted stock units		5				5
Vested restricted stock units (in shares)		4,816
Shares withheld for employee taxes related to vested restricted stock units		(1)	(11,138)			(11,139)
Shares withheld for employee taxes related to vested restricted stock units (in shares)		(1,418)
Common stock issued to former employees of Quantum		3				3
Common stock issued to former employees of Quantum (See Note 3) (in shares)		3,152
Repurchase of common stock	(89,200)	(12)	(89,204)			(89,216)
Repurchase of common stock (in shares)	(11,700)	(11,720)
Balances at Dec. 31, 2010		457	1,273,853	16,329	(237,583)	1,053,056
Balances (in shares) at Dec. 31, 2010		456,788
Comprehensive income (loss):
Net income	314,990					314,990
Actuarial losses related to defined benefit pension plans	(197)			(197)		(197)
Unrealized (losses) gains on investments				179
Unrealized losses on investments, net of tax						179
Inclusion of foreign CTA adjustments in net income	0
Foreign currency translation adjustments (CTA)	(6,863)			(6,863)		(6,863)
Total comprehensive income	308,109					308,109
Stock-based compensation expense			69,102			69,102
Tax benefit on stock-based compensation expense			939			939
Exercise of stock options		4	19,336			19,340
Exercise of stock options (in shares)		4,285
Issuance of commons stock under employee stock purchase plan		2	9,404			9,406
Issuance of common stock under employee stock purchase plan (in shares)		1,514
Vested restricted stock units		6				6
Vested restricted stock units (in shares)		6,345
Vested performance restricted stock units		8				8
Vested performance-based restricted stock units (in shares)		8,485
Shares withheld for employee taxes related to vested restricted stock units		(6)	(73,280)			(73,286)
Shares withheld for employee taxes related to vested restricted stock units (in shares)		(6,252)
Repurchase of common stock	(304,200)	(29)	(304,207)			(304,236)
Repurchase of common stock (in shares)	(28,800)	(28,776)
Balances at Dec. 31, 2011	1,082,444	442	995,147	9,448	77,407	1,082,444
Balances (in shares) at Dec. 31, 2011		442,389
Comprehensive income (loss):
Net income	30,445					30,445
Actuarial losses related to defined benefit pension plans	(6,778)			(6,778)		(6,778)
Unrealized (losses) gains on investments				(160)
Unrealized losses on investments, net of tax						(160)
Inclusion of foreign CTA adjustments in net income	0
Foreign currency translation adjustments (CTA)	3,902			3,902		3,902
Total comprehensive income	27,409					27,409
Stock-based compensation expense			71,974			71,974
Equity related restructuring charges			413			413
Tax benefit on stock-based compensation expense			(1,738)			(1,738)
Exercise of stock options		2	4,578			4,580
Exercise of stock options (in shares)		1,239
Issuance of commons stock under employee stock purchase plan		2	10,955			10,957
Issuance of common stock under employee stock purchase plan (in shares)		1,770
Vested restricted stock units		8				8
Vested restricted stock units (in shares)		7,975
Shares withheld for employee taxes related to vested restricted stock units		(2)	(19,828)			(19,830)
Shares withheld for employee taxes related to vested restricted stock units (in shares)		(2,100)
Repurchase of common stock	(179,600)	(23)	(179,556)			(179,579)
Repurchase of common stock (in shares)	(22,700)	(22,680)
Balances at Dec. 31, 2012	$ 996,638	$ 429	$ 881,945	$ 6,412	$ 107,852	$ 996,638
Balances (in shares) at Dec. 31, 2012		428,593