Schedule of Calculation of Numerator and Denominator in Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
INCOME FROM CONTINUING OPERATIONS	$ 51,738	$ 181,447
Loss from discontinued operations, net of taxes		(355)
Net income	51,738	181,092
Weighted average shares and assumed conversions	116,960	101,835
Income from continuing operations	$ 0.45	$ 1.81
Loss from discontinued operations, net of taxes
Net income	$ 0.45	$ 1.81
Income from continuing operations	$ 0.44	$ 1.78
Loss from discontinued operations, net of taxes
Net income	$ 0.44	$ 1.78
Basic Earnings Per Share
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
INCOME FROM CONTINUING OPERATIONS	51,738	181,447
Loss from discontinued operations, net of taxes		(355)
Net income	51,738	181,092
Weighted average common shares outstanding, basic	115,773	100,070
Diluted Earnings Per Share
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
INCOME FROM CONTINUING OPERATIONS	51,738	181,447
Loss from discontinued operations, net of taxes		(355)
Net income	$ 51,738	$ 181,092
Weighted average common shares outstanding, diluted	115,773	100,070
Stock options
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities	963	1,556
Restricted stock based compensation
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Effect of dilutive securities	224	209