Basis of Presentation and Accounting Policies - Schedule of Company's Reconciliation of Level 3 Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Investment Securities Available For Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 2,000	$ 2,000
Total gains (losses) included in net income
Purchases, sales, issuances, and settlements, net
Transfers in or out of Level 3
Asset reclassification, within Level 3
Ending balance	2,000	2,000
Impaired Loans Carried at Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	42,546	52,514
Transfers in or out of Level 3		1,262
Asset reclassification, within Level 3	(1,293)	(2,626)
Ending balance	41,253	51,150
Other Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	33,351	39,850
Total gains (losses) included in net income	(750)	(15)
Purchases, sales, issuances, and settlements, net	(1,316)	(2,027)
Transfers in or out of Level 3	1,261
Asset reclassification, within Level 3	1,293	2,626
Ending balance	33,839	40,434
Purchased Non-Covered Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	448,753
Purchases, sales, issuances, and settlements, net	(11,416)
Asset reclassification, within Level 3	(68)
Ending balance	437,269
Purchased Non-Covered Other Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	4,276
Total gains (losses) included in net income	(46)
Purchases, sales, issuances, and settlements, net	(529)
Transfers in or out of Level 3	95
Asset reclassification, within Level 3	68
Ending balance	3,864
Covered Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	390,237	507,712
Purchases, sales, issuances, and settlements, net	(12,617)	(31,449)
Asset reclassification, within Level 3	(4,926)	(15,539)
Ending balance	372,694	460,724
Covered Other Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	45,893	88,273
Total gains (losses) included in net income	(219)	(3,032)
Purchases, sales, issuances, and settlements, net	(7,964)	(22,865)
Asset reclassification, within Level 3	4,926	15,539
Ending balance	$ 42,636	$ 77,915