CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balances at Dec. 31, 2010	$ 1,218,526	$ 634	$ 191,674	$ (423)	$ 1,042,123	$ (15,482)
Balances (in shares) at Dec. 31, 2010		63,412,800		102,635
Increase (Decrease) in Stockholders' Equity
Net income (loss)	215,416				215,416
Other comprehensive income (loss)	11,202					11,202
Cash dividends, $ 0.10 per share	(6,382)				(6,382)
Issuance of common stock under Employee Stock Purchase Plan	2,300	0	2,300
Issuance of common stock under Employee Stock Purchase Plan (in shares)		41,358
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings	(9,973)	3	(9,976)
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (in shares)		278,773
Issuance of common stock upon stock option exercises	5,027	4	5,023
Issuance of common stock upon stock option exercises (in shares)		412,551
Stock-based compensation expense	26,824		27,945	(1,121)
Stock-based compensation expense, Shares		0		21,568
Balances at Dec. 31, 2011	1,462,940	641	216,966	(1,544)	1,251,157	(4,280)
Balances (in shares) at Dec. 31, 2011		64,145,482		81,067
Common Stock, Dividends, Per Share, Declared	$ 0.10
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(54,249)				(54,249)
Other comprehensive income (loss)	(4,734)					(4,734)
Cash dividends, $ 0.10 per share	(6,511)				(6,511)
Issuance of common stock under Employee Stock Purchase Plan	2,776	1	2,775
Issuance of common stock under Employee Stock Purchase Plan (in shares)		66,485
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings	(21,622)	9	(21,631)
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (in shares)		929,375
Issuance of common stock upon stock option exercises	3,040	2	3,038
Issuance of common stock upon stock option exercises (in shares)		240,368
Conversion of 3.50% Senior Convertible Notes to common stock, including income tax benefit of conversion	2,641	9	2,632
Conversion of 3.50% Senior Convertible Notes to common stock, including income tax benefit of conversion (in shares)		864,106
Stock-based compensation expense	30,185		29,862	323
Stock-based compensation expense, Shares		0		30,486
Balances at Dec. 31, 2012	1,414,466	662	233,642	(1,221)	1,190,397	(9,014)
Balances (in shares) at Dec. 31, 2012		66,245,816		50,581
Common Stock, Dividends, Per Share, Declared	$ 0.10
Increase (Decrease) in Stockholders' Equity
Net income (loss)	170,935				170,935
Other comprehensive income (loss)	3,598					3,598
Cash dividends, $ 0.10 per share	(6,663)				(6,663)
Issuance of common stock under Employee Stock Purchase Plan	3,672	1	3,671
Issuance of common stock under Employee Stock Purchase Plan (in shares)		77,427
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings	(16,220)	5	(16,225)
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (in shares)		526,852
Issuance of common stock upon stock option exercises	3,186	3	3,183
Issuance of common stock upon stock option exercises (in shares)		228,758
Stock-based compensation expense	32,347		31,949	398
Stock-based compensation expense, Shares		0		28,169
Other income tax benefit	1,500		1,500
Balances at Dec. 31, 2013	$ 1,606,821	$ 671	$ 257,720	$ (823)	$ 1,354,669	$ (5,416)
Balances (in shares) at Dec. 31, 2013		67,078,853		22,412