Income Taxes - Components of Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Income tax expense from continuing operations	$ 234,654	$ 236,669	$ 226,166
Income tax expense (benefit) from discontinued operations	0	0	(467)
Other comprehensive income (loss)	(386,752)	201,950	284,355
Tax basis compensation expense (from the exercise of stock options and vesting of restricted stock awards) in excess of amounts recognized for financial reporting purposes	(21,314)	(22,602)	(13,121)
Income tax expense, Total	$ (173,412)	$ 416,017	$ 496,933