Acquired and Covered Loans (Detail) - Acquired and Covered Loans - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Acquired Loans [Line Items]
Non-PCI	$ 555,362	$ 739,589
Total	615,567	822,983
Acquired Loans
Acquired Loans [Line Items]
Non-PCI	534,506	714,836
Total	584,792	743,548
Covered Loans
Acquired Loans [Line Items]
Non-PCI	20,856	24,753
Total	30,775	79,435
Receivables Acquired with Deteriorated Credit Quality [Member]
Acquired Loans [Line Items]
PCI	60,205	83,394
Receivables Acquired with Deteriorated Credit Quality [Member] | Acquired Loans
Acquired Loans [Line Items]
PCI	50,286	28,712
Receivables Acquired with Deteriorated Credit Quality [Member] | Covered Loans
Acquired Loans [Line Items]
PCI	$ 9,919	$ 54,682