Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net Income (Loss) (Numerator)
Basic earnings per share - net income (in dollars)	$ 62,737	$ 30,761
Diluted earnings per share - net income (in dollars)	$ 62,737	$ 30,761
Weighted average common shares outstanding (in shares)
Weighted average common shares outstanding - basic (in shares)	243,202,000	241,535,000
Dilutive common share equivalents (in shares)	1,406,000	1,332,000
Weighted average common shares outstanding - diluted (in shares)	244,608,000	242,867,000
Per Share Amount
Basic (in dollars per share)	$ 0.26	$ 0.13
Diluted (in dollars per share)	$ 0.26	$ 0.13
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