Loans and Allowance for Loan Losses - Summary of Troubled Debt Restructurings, Excluding Purchased Non-Covered and Covered Loans, by Collateral Types (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring loans	$ 20,900	$ 23,900
Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring loans	17,214	18,744	17,951
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	72	55
Troubled debt restructuring loans	17,214	18,744
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Warehouse [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4	3
Troubled debt restructuring loans	1,346	1,692
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Raw Land [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	11	2
Troubled debt restructuring loans	2,345	1,337
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Hotel & Motel [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3	3
Troubled debt restructuring loans	2,185	2,318
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Office [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4	4
Troubled debt restructuring loans	1,909	2,105
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Retail, Including Strip Centers [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4	6
Troubled debt restructuring loans	1,095	2,833
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	36	31
Troubled debt restructuring loans	7,747	7,651
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Life Insurance Policy [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1
Troubled debt restructuring loans	250	250
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Automobile/Equipment/Inventory [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	8	4
Troubled debt restructuring loans	92	508
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Unsecured [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1
Troubled debt restructuring loans	245	50
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	20	5
Troubled debt restructuring loans	3,683	5,171
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Warehouse [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2	1
Troubled debt restructuring loans	592	177
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Raw Land [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2
Troubled debt restructuring loans	32
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Office [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts		1
Troubled debt restructuring loans		2,770
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Retail, Including Strip Centers [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2	1
Troubled debt restructuring loans	1,680	1,202
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	9	2
Troubled debt restructuring loans	852	1,022
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Automobile/Equipment/Inventory [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4
Troubled debt restructuring loans	479
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Unsecured [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1
Troubled debt restructuring loans	$ 48