CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (in thousands, except share data and dividends per share) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Cash dividends per share	$ 0.10
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2016		111,257,500
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2016	$ 2,497,133	$ 1,113	$ 1,716,556	$ 794,020	$ (14,556)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(160,843)			(160,843)
Other comprehensive income	767				767
Cash dividends, $ 0.10 per share	(11,144)			(11,144)
Issuance of common stock under Employee Stock Purchase Plan (Shares)		186,665
Issuance of common stock under Employee Stock Purchase Plan (Amount)	2,623	$ 2	2,621
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		171,278
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(1,240)	$ 1	(1,241)
Stock-based compensation expense (Shares)		71,573
Stock-based compensation expense (Amount)	22,700	$ 1	22,699
Other	(120)		(120)
Balances, Common Stock, Shares, Outstanding, Ending at Dec. 31, 2017		111,687,016
Balances, Total Stockholders' Equity, Ending at Dec. 31, 2017	$ 2,394,608	$ 1,117	1,741,623	665,657	(13,789)
Cash dividends per share	$ 0.10
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ 508,407			508,407
Other comprehensive income	4,378				4,378
Cash dividends, $ 0.10 per share	(11,191)			(11,191)
Issuance of common stock under Employee Stock Purchase Plan (Shares)		199,464
Issuance of common stock under Employee Stock Purchase Plan (Amount)	3,187	$ 2	3,185
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		291,745
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(2,975)	$ 3	(2,978)
Stock-based compensation expense (Shares)		63,741
Stock-based compensation expense (Amount)	$ 23,908	$ 0	23,908
Balances, Common Stock, Shares, Outstanding, Ending at Dec. 31, 2018	112,241,966	112,241,966
Balances, Total Stockholders' Equity, Ending at Dec. 31, 2018	$ 2,920,322	$ 1,122	1,765,738	1,165,842	(12,380)
Cash dividends per share	$ 0.10
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ (187,001)			(187,001)
Other comprehensive income	1,061				1,061
Cash dividends, $ 0.10 per share	(11,254)			(11,254)
Issuance of common stock under Employee Stock Purchase Plan (Shares)		314,868
Issuance of common stock under Employee Stock Purchase Plan (Amount)	3,209	$ 3	3,206
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		334,399
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(1,661)	$ 4	(1,665)
Stock-based compensation expense (Shares)		96,719
Stock-based compensation expense (Amount)	$ 24,318	$ 1	24,317
Balances, Common Stock, Shares, Outstanding, Ending at Dec. 31, 2019	112,987,952	112,987,952
Balances, Total Stockholders' Equity, Ending at Dec. 31, 2019	$ 2,748,994	$ 1,130	$ 1,791,596	$ 967,587	$ (11,319)