Acquisition Activity (Detail) $ in Millions	9 Months Ended
Sep. 30, 2016 USD ($)
Business Acquisition
Maximum period for subject to change estimated fair values after acquisition date	1 year
Florida Bank Group Inc. and Old Florida Bancshares Inc.
Business Acquisition
Increase in goodwill due to purchase price allocations	$ 2.3

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=73531572&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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