Loans and Allowance for Loan Losses - Summary of Troubled Debt Restructurings, Excluding Purchased Non-Covered and Covered Loans, by Concessions Made 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] | Forbearance of Interest [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	10	2
Troubled debt restructuring loans	2,170	1,873
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Forgiveness of Principal [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3	3
Troubled debt restructuring loans	1,467	1,518
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Payment Modification Only [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	2
Troubled debt restructuring loans	280	376
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Rate Reduction Only [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	14	11
Troubled debt restructuring loans	7,069	7,075
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Rate Reduction, Forbearance of Interest [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	26	18
Troubled debt restructuring loans	3,252	4,061
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Rate Reduction, Forbearance of Principal [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	18	18
Troubled debt restructuring loans	2,976	3,798
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Rate Reduction, Payment Modification [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts		1
Troubled debt restructuring loans		43
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] | Forbearance of Interest [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2
Troubled debt restructuring loans	97
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Forgiveness of Principal [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1
Troubled debt restructuring loans	145	372
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Payment Modification Only [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1
Troubled debt restructuring loans	88
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Rate Reduction Only [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3	1
Troubled debt restructuring loans	913	177
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Rate Reduction, Forbearance of Interest [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	12	2
Troubled debt restructuring loans	2,411	3,420
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Rate Reduction, Payment Modification [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1
Troubled debt restructuring loans	$ 29	$ 1,202