Carrying Amounts And Fair Values of the Company's Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financial Assets
Investments held-to-maturity and other equity securities	$ 197,862	$ 213,398
Loans, net of allowance	2,429,813	2,190,266
Other assets	82,392	81,098
Financial Liabilities
Time Deposits	603,552	584,321
Securities sold under retail repurchase agreements and federal funds purchased	64,779	143,613
Advances from FHLB	405,233	405,408
Subordinated debentures	35,000	35,000
Financial Assets
Investments held-to-maturity and other equity securities	202,412	219,100
Loans, net of allowance	2,506,993	2,276,333
Other assets	82,392	81,098
Financial Liabilities
Time Deposits	606,810	588,818
Securities sold under retail repurchase agreements and federal funds purchased	64,779	143,613
Advances from FHLB	452,562	452,378
Subordinated debentures	9,713	9,810
Fair Value, Inputs, Level 2
Financial Assets
Investments held-to-maturity and other equity securities	202,412	219,100
Other assets	82,392	81,098
Financial Liabilities
Time Deposits	606,810	588,818
Securities sold under retail repurchase agreements and federal funds purchased	64,779	143,613
Advances from FHLB	452,562	452,378
Fair Value, Inputs, Level 3
Financial Assets
Loans, net of allowance	2,506,993	2,276,333
Financial Liabilities
Subordinated debentures	$ 9,713	$ 9,810