Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		142		1,431
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	$ 0.005	$ 0.01	$ 0.01	$ 0.01
Net Income (Loss) Attributable to Parent [Abstract]
Net income attributable to common stockholders	$ 47,448	$ 17,651	$ 161,418	$ 84,675
After tax interest on convertible debt	13		37	38
Net income — diluted	$ 47,461	$ 17,651	$ 161,455	$ 84,713
Weighted average shares (denominator):
Weighted average shares — basic	(199,310)	(210,820)	(201,729)	(212,009)
Stock options	4,013	2,190	4,100	3,235
Convertible debt	121	0	121	121
Weighted average shares — diluted	203,444	213,010	205,950	215,365
Net income attributable to common stockholders, basic	$ 0.24	$ 0.08	$ 0.80	$ 0.40
Net income attributable to common stockholders, diluted	$ 0.23	$ 0.08	$ 0.78	$ 0.39
Equity Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		21		1,431
Antidilutive Convertible Debentures [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		121