Investment Securities (Amortized Cost And Fair Value Of Available-For-Sale Securities By Contractual Maturity) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Fair Value	$ 9,428
Due from one year to five years, Fair Value	19,420
Due from five to ten years, Fair Value	61,179
Due after ten years, Fair Value	42,105
Mortgage-backed securities, Fair Value	228,919
Fair Value	361,051	339,967	340,839
Due in one year or less, Amortized Cost	9,385
Due from one year to five years, Amortized Cost	18,605
Due from five to ten years, Amortized Cost	57,227
Due after ten years, Amortized Cost	41,723
Mortgage-backed securities, Amortized Cost	222,641
Mortgage-backed securities, Amortized Cost	$ 349,581	$ 330,060	$ 330,917

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

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