Loans - Summary of Troubled Debt Restructurings Included in Covered Loans by Collateral Types (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring loans	$ 21,200	$ 20,900	$ 23,300
Covered Loans [Member] | Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	103	100	75
Troubled debt restructuring loans	22,775	22,243	19,762
Covered Loans [Member] | Accruing Loans [Member] | Warehouse [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts			1
Troubled debt restructuring loans			379
Covered Loans [Member] | Accruing Loans [Member] | Raw Land [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1	4
Troubled debt restructuring loans	374	375	2,496
Covered Loans [Member] | Accruing Loans [Member] | Hotel & Motel [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	7	6	6
Troubled debt restructuring loans	4,867	5,118	3,650
Covered Loans [Member] | Accruing Loans [Member] | Office [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2	1	1
Troubled debt restructuring loans	1,342	855	855
Covered Loans [Member] | Accruing Loans [Member] | Retail, Including Strip Centers [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	5	6	7
Troubled debt restructuring loans	3,819	3,853	3,769
Covered Loans [Member] | Accruing Loans [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	87	85	54
Troubled debt restructuring loans	12,359	12,029	8,563
Covered Loans [Member] | Accruing Loans [Member] | Automobile/Equipment/Inventory [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts			1
Troubled debt restructuring loans			36
Covered Loans [Member] | Accruing Loans [Member] | Unsecured [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1	1
Troubled debt restructuring loans	14	13	14
Covered Loans [Member] | Non-Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	27	24	20
Troubled debt restructuring loans	5,025	5,021	7,794
Covered Loans [Member] | Non-Accruing Loans [Member] | Warehouse [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2	1
Troubled debt restructuring loans	486	377
Covered Loans [Member] | Non-Accruing Loans [Member] | Raw Land [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	5	3	2
Troubled debt restructuring loans	59	37	772
Covered Loans [Member] | Non-Accruing Loans [Member] | Hotel & Motel [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts		1	1
Troubled debt restructuring loans		155	166
Covered Loans [Member] | Non-Accruing Loans [Member] | Office [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	1	1	1
Troubled debt restructuring loans	73	78	87
Covered Loans [Member] | Non-Accruing Loans [Member] | Retail, Including Strip Centers [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3	2	4
Troubled debt restructuring loans	3,287	3,337	4,732
Covered Loans [Member] | Non-Accruing Loans [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	11	11	11
Troubled debt restructuring loans	1,052	966	2,037
Covered Loans [Member] | Non-Accruing Loans [Member] | Automobile/Equipment/Inventory [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	5	5	1
Troubled debt restructuring loans	$ 68	$ 71