Investment Securities (Amortized Cost And Fair Value Of Available-For-Sale Securities By Contractual Maturity) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	$ 9,306
Due from one year to five years, Amortized Cost	18,553
Due from five to ten years, Amortized Cost	51,174
Due after ten years, Amortized Cost	36,715
Mortgage-backed securities, Amortized Cost	239,412
Mortgage-backed securities, Amortized Cost	355,160	330,060	328,766
Due in one year or less, Fair Value	9,320
Due from one year to five years, Fair Value	19,264
Due from five to ten years, Fair Value	54,892
Due after ten years, Fair Value	37,255
Mortgage-backed securities, Fair Value	246,249
Fair Value	$ 366,980	$ 339,967	$ 334,376

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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