Loans and Allowance for Loan Losses - Summary of Troubled Debt Restructurings, Included in Purchased Non-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
Purchased Non-Covered Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring loans	5,938
Purchased Non-Covered Loans [Member] | Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	24
Troubled debt restructuring loans	5,938
Purchased Non-Covered Loans [Member] | Accruing Loans [Member] | Warehouse [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts
Troubled debt restructuring loans
Purchased Non-Covered Loans [Member] | Accruing Loans [Member] | Raw Land [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	6
Troubled debt restructuring loans	2,640
Purchased Non-Covered Loans [Member] | Accruing Loans [Member] | Office [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1
Troubled debt restructuring loans	803
Purchased Non-Covered Loans [Member] | Accruing Loans [Member] | Retail, Including Strip Centers [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2
Troubled debt restructuring loans	425
Purchased Non-Covered Loans [Member] | Accruing Loans [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	13
Troubled debt restructuring loans	2,053
Purchased Non-Covered Loans [Member] | Accruing Loans [Member] | Automobile/Equipment/Inventory [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2
Troubled debt restructuring loans	17
Purchased Non-Covered Loans [Member] | Non-Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	10
Troubled debt restructuring loans	1,212
Purchased Non-Covered Loans [Member] | Non-Accruing Loans [Member] | Warehouse [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1
Troubled debt restructuring loans	468
Purchased Non-Covered Loans [Member] | Non-Accruing Loans [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	8
Troubled debt restructuring loans	738
Purchased Non-Covered Loans [Member] | Non-Accruing Loans [Member] | Automobile/Equipment/Inventory [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1
Troubled debt restructuring loans	$ 6