Income Taxes (Provision for Income Taxes) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Contingency [Line Items]
Current Federal Tax Expense (Benefit)	$ 134,619	$ 104,152	$ 83,569
Current State and Local Tax Expense (Benefit)	3,726	1	1
Current Income Tax Expense (Benefit)	138,345	104,153	83,570
Deferred Federal Income Tax Expense (Benefit)	(416)	11,311	24,469
Deferred State and Local Income Tax Expense (Benefit)	(583)	0	0
Deferred Income Tax Expense (Benefit)	(999)	11,311	24,469
Income Tax Expense (Benefit)	$ 137,346	$ 115,464	$ 108,039