Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Income (Loss) (Numerator)
Basic earnings per share - net income (in dollars)	$ 141,969	$ 31,550	$ 204,706	$ 62,311
Diluted earnings per share - net income (in dollars)	$ 141,969	$ 31,550	$ 204,706	$ 62,311
Weighted average common shares outstanding (in shares)
Weighted average common shares outstanding - basic (in shares)	243,655,000	241,900,000	243,429,000	241,718,000
Dilutive common share equivalents (in shares)	1,737,000	1,591,000	1,571,000	1,461,000
Weighted average common shares outstanding - diluted (in shares)	245,392,000	243,491,000	245,000,000	243,179,000
Per Share Amount
Basic (in dollars per share)	$ 0.58	$ 0.13	$ 0.84	$ 0.26
Diluted (in dollars per share)	$ 0.58	$ 0.13	$ 0.84	$ 0.26
Options
Antidilutive securities excluded from computation of earnings per share amount
Antidilutive common share equivalents excluded from computation of earnings per share amount (in shares)	0	0	0	0