Estimated Fair Value Of Financial Instruments (Summary Of The Difference Between The Aggregate Fair Value And Remaining Principle Balance In Mortgage Loans Held For Sale) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Estimated Fair Value Of Financial Instruments [Line Items]
Mortgage loans held for sale	$ 35,342		$ 32,049
Aggregate Fair Value [Member]
Estimated Fair Value Of Financial Instruments [Line Items]
Mortgage loans held for sale	35,342	[1]	32,049	[1]
Difference [Member]
Estimated Fair Value Of Financial Instruments [Line Items]
Mortgage loans held for sale	(3)	[1]	(120)	[1]
Aggregate Unpaid Principal Balance [Member]
Estimated Fair Value Of Financial Instruments [Line Items]
Mortgage loans held for sale	$ 35,339	[1]	$ 31,929	[1]

[1] The change in fair value is reflected in mortgage banking non-interest income.