CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent
Cash dividends per share	$ 0.05
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2017		111,687,016
Balances, Total stockholders' equity, beginning at Dec. 31, 2017	$ 2,394,608	$ 1,117	$ 1,741,623	$ 665,657	$ (13,789)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	317,401			317,401
Other comprehensive income	260				260
Cash dividends declared, $0.05 per share	(5,584)			(5,584)
Stock-based compensation expense	5,412		5,412
Other	0			1	(1)
Balances, Common Stock, Shares, Outstanding, Ending at Mar. 31, 2018		111,687,016
Balances, Total stockholders' equity, ending at Mar. 31, 2018	2,712,097	$ 1,117	1,747,035	980,444	(16,499)
Increase (Decrease) in Stockholders' Equity
Cumulative effect of accounting change	$ 0			2,969	(2,969)
Cash dividends per share	$ 0.05
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2018	112,241,966	112,241,966
Balances, Total stockholders' equity, beginning at Dec. 31, 2018	$ 2,920,322	$ 1,122	1,765,738	1,165,842	(12,380)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(177,568)			(177,568)
Other comprehensive income	263				263
Cash dividends declared, $0.05 per share	(5,612)			(5,612)
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		2,579
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(18)	$ 0	(18)
Stock-based compensation expense	$ 5,838		5,838
Balances, Common Stock, Shares, Outstanding, Ending at Mar. 31, 2019	112,244,545	112,244,545
Balances, Total stockholders' equity, ending at Mar. 31, 2019	$ 2,743,225	$ 1,122	$ 1,771,558	$ 982,662	$ (12,117)