Note FDIC loss share (expense) income (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Disclosure F D I C Loss Share Expense Income [Abstract]
Accretion of loss share indemnification asset, net		$ (934)	$ (776)
80% mirror accounting on credit impairment losses (reversal)	[1]	104	148
80% mirror accounting on reimbursable expenses		537	921
80% mirror accounting on recoveries on covered assets, including rental income on OREOs, subject to reimbursement to the FDIC		(1,658)	4,833
Change in true-up payment obligation		(6,112)	(7,385)
Other		36	(5,998)
FDIC loss share (expense) income		$ (8,027)	$ (8,257)

[1] Reductions in expected cash flows for ASC 310-30 loans, which may impact the provision for loan losses, may consider reductions in both principal and interest cash flow expectations. The amount covered under the FDIC loss sharing agreements for interest not collected from borrowers is limited under the agreements (approximately 90 days); accordingly, these amounts are not subject fully to the 80% mirror accounting.