Loss Sharing Agreements and FDIC Loss Share Receivable (Detail) $ in Millions		24 Months Ended
Dec. 20, 2016 USD ($)	Dec. 31, 2010 bank
Loss Sharing Agreements and FDIC Loss Share Receivable [Abstract]
Number of acquisitions \| bank		6
Cash received upon termination of loss-share agreements	$ 6.5
Loss on termination of loss-share agreements	$ 17.8

The loss recognized on termination of a contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 275
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68065670&loc=d3e54681-109401

Name:	us-gaap_LossOnContractTermination
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration