Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Net Income (Loss) Attributable to Parent [Abstract]
Net income — basic	$ 41,102	$ 57,620
After tax interest on convertible debt	13	13
Net income — diluted	$ 41,115	$ 57,633
Weighted average shares (denominator):
Weighted average shares — basic	(212,838)	(211,380)
Stock options	4,272	3,707
Convertible debt	121	121
Weighted average shares — diluted	217,231	215,208
Net income attributable to common stockholders	$ 0.19	$ 0.27
Net income attributable to common stockholders	$ 0.19	$ 0.27