Income Taxes - Income Tax Expense from Continuing Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Components Of Income Tax Expense Benefit Continuing Operations [Abstract]
Income tax expense	$ 93,522	$ 11,866	$ 230,455	$ 62,180
Effective tax rate	39.00%	38.20%	39.70%	41.50%