Per Share Information - Basic and Diluted Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Amounts attributable to common stock:
Net income from continuing operations	$ 20,496	$ 47,689
Net income from discontinued operations		5,795
Net income attributable to common stock	$ 20,496	$ 53,484
Weighted average shares:
Weighted average shares outstanding for basic earnings per share	162,803	215,473
Effect of dilutive stock options	3	17
Weighted average shares outstanding for diluted earnings per share	162,806	215,490