CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (UNAUDITED) (in thousands, except share amounts) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Dividends per common share		$ 0.10
Balances, Common Shares, Beginning at Dec. 31, 2016		111,257,500	111,257,500
Balances, Beginning at Dec. 31, 2016		$ 2,497,133	$ 1,113	$ 1,716,556	$ 794,020	$ (14,556)
Increase (Decrease) in Stockholders' Equity
Net loss		(134,585)			(134,585)
Other comprehensive loss		(651)				(651)
Dividends, $0.10 per share		(11,144)			(11,144)
Issuance of common stock under Employee Stock Purchase Plan (in shares)			123,678
Issuance of common stock under Employee Stock Purchase Plan		1,738	$ 1	1,737
Issuance of common stock upon vesting of restricted stock units, net of shares used for tax withholdings (in shares)			171,278
Issuance of common stock upon vesting of restricted stock units, net of shares used for tax withholdings		(1,240)	$ 1	(1,241)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			71,573
Stock-based compensation expense		16,160	$ 1	16,159
Cumulative effect of accounting change	[1]	44,732		1,108	43,624
Other		$ (102)		(102)
Balances, Common Shares, Ending at Sep. 30, 2017		111,624,029	111,624,029
Balances, Ending at Sep. 30, 2017		$ 2,412,041	$ 1,116	$ 1,734,217	$ 691,915	$ (15,207)

[1] (1) Refer to Note 2 - Basis of Presentation, Significant Accounting Policies, and Recently Issued Accounting Standards.