Borrowed Funds (Detail) - Unused Short-Term Credit Lines Available for Use (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Debt Disclosure [Abstract]
Available federal funds lines	$ 681,100	[1]	$ 500,600	[1]
Federal Reserve Bank’s Discount Window primary credit program	$ 632,498		$ 1,625,826

[1] Subject to the liquidity position of other banks.