Consolidated Statement of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in-Capital	Retained Earnings (Deficit)
Balance, shares at Dec. 31, 2012		93,303	129
Balance at Dec. 31, 2012	$ 795,005	$ 925	$ (3,796)	$ 657,943	$ 139,933
Issuance of common stock	314,580	$ 70		314,510
Issuance of common stock, shares		7,000
Stock-based compensation	12,571			12,571
Stock-based compensation, shares		434
Vesting of restricted shares		$ 1		(1)
Treasury stock - tax withholdings	1,566		$ 1,566
Treasury stock - tax withholdings, shares		(38)	38
Net income (loss)	227,959				227,959
Balance at Dec. 31, 2013	1,348,549	$ 996	$ (5,362)	985,023	367,892
Balance, shares at Dec. 31, 2013		100,699	167
Fees (2013 issuance of common stock)	(176)			(176)
Stock-based compensation	22,360			22,360
Stock-based compensation, shares		762
Vesting of restricted shares		$ 5		(5)
Treasury stock - tax withholdings	5,309		$ 5,309
Treasury stock - tax withholdings, shares		(119)	119
Net income (loss)	506,877				506,877
Balance at Dec. 31, 2014	1,872,301	$ 1,001	$ (10,671)	1,007,202	874,769
Balance, shares at Dec. 31, 2014		101,342	286
Issuance of common stock	462,833	$ 368		462,465
Issuance of common stock, shares		36,800
Stock-based compensation	27,405			27,405
Stock-based compensation, shares		1,156
Vesting of restricted shares		$ 7		(7)
Treasury stock - tax withholdings	2,949		$ 2,949
Treasury stock - tax withholdings, shares		(222)	222
Net income (loss)	(40,248)				(40,248)
Balance at Dec. 31, 2015	$ 2,319,342	$ 1,376	$ (13,620)	$ 1,497,065	$ 834,521
Balance, shares at Dec. 31, 2015		139,076	508