Reconciliation of Statutory Federal Income Tax Expense (Benefit) to Combined Actual Income Tax Expense (Benefit) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliation of Provision of Income Taxes [Line Items]
Statutory federal income tax expense at 35%	$ 257,102	$ 293,115	$ 207,602
State and local income taxes, net of federal income tax effect	25,306	26,525	20,719
Effect of tax deductibility of ESOP	(6,739)	(5,243)	(5,666)
Non-taxable income and expense of BOLI	(9,848)	(9,805)	(9,592)
Federal tax credits	(6,194)	(5,955)	(6,048)
Adjustments relating to prior tax years	(5,152)	(1,342)	(13,160)
Other, net	65	(841)	648
Total income tax expense	$ 254,540	$ 296,454	$ 194,503