Note FDIC loss share (expense) income - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
F D I C Loss Share Expense Income [Line Items]
F D I C Indemnification Asset Accretion Of Discount	$ 4,042	$ 27,316
FDIC
F D I C Loss Share Expense Income [Line Items]
Limited Period For The F D I C Loss Sharing Agreements Covered For Interest Not Collected	approximately 90 days