Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net income (loss) available to stockholders	$ (20,370)	$ 36,410	$ (55,907)	$ 63,349
Less: preferred stock dividends	0	0	0	15
Net income (loss) available to common stockholders	$ (20,370)	$ 36,410	$ (55,907)	$ 63,334
Weighted average shares outstanding, basic	70,493	69,684	70,318	69,584
Dilutive common stock equivalents	0	2,817	0	2,811
Weighted average shares outstanding, diluted	70,493	72,501	70,318	72,395
Earnings (loss) per share, basic	$ (0.29)	$ 0.52	$ (0.80)	$ 0.91
Earnings (loss) per share, diluted	$ (0.29)	$ 0.50	$ (0.80)	$ 0.87
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	11		25