Basis Of Presentation And Accounting Policies (Fair Value Of Assets And Liabilities Measured As Fair Value On Recurring Basis) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	$ 386,639	$ 337,918	$ 334,619
Recurring liabilities at fair value	2,970
U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	8,898	14,937	24,259
State, county and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	100,327	79,133	60,546
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	11,506	11,401	9,722
Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	246,249	234,496	239,849
Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value		2,049	243
Recurring liabilities at fair value	2,970
Mortgage loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	19,659
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	10,768	6,268	10,520
Level 1 | State, county and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	5,432	2,966	2,367
Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	250
Level 1 | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	5,086	3,302	8,153
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	373,871	329,650	322,099
Recurring liabilities at fair value	2,970
Level 2 | U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	8,898	14,937	24,259
Level 2 | State, county and municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	94,895	76,167	58,179
Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	9,256	9,401	7,722
Level 2 | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	241,163	231,194	231,696
Level 2 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value		2,049	243
Recurring liabilities at fair value	2,970
Level 2 | Mortgage loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	19,659
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value	2,000	2,000	2,000
Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Recurring assets at fair value		$ 2,000	$ 2,000