Acquisition Activity - Schedule of Business Acquisitions, by Acquisition (Detail) - USD ($) $ in Thousands	May. 31, 2015	Mar. 31, 2015	Feb. 28, 2015	Sep. 30, 2015
Florida Bank Group, Inc.
Assets
Cash and cash equivalents			$ 72,982	$ 72,982
Investment securities			107,236	107,372
Loans			312,902	305,829
Other real estate owned			498	423
Core deposit intangible			0	4,489
Deferred tax asset, net			19,889	29,121
Other assets			29,810	20,861
Total Assets			543,317	541,077
Liabilities
Interest-bearing deposits			282,417	282,680
Non-interest-bearing deposits			109,548	109,548
Borrowings			60,000	68,598
Other liabilities			1,897	6,515
Total Liabilities			$ 453,862	467,341
Estimated amortized period for fair value adjustment			51 months
Old Florida Bancshares, Inc.
Assets
Cash and cash equivalents		$ 360,688		360,688
Investment securities		67,209		67,209
Loans held for sale		5,952		5,952
Loans		1,073,773		1,064,431
Other real estate owned		4,515		4,513
Core deposit intangible		0		10,055
Deferred tax asset, net		8,470		11,651
Other assets		30,732		23,494
Total Assets		1,551,339		1,547,993
Liabilities
Interest-bearing deposits		1,048,765		1,048,888
Non-interest-bearing deposits		340,869		340,869
Borrowings		1,528		1,528
Other liabilities		3,011		3,087
Total Liabilities		$ 1,394,173		1,394,372
Estimated amortized period for fair value adjustment		56 months
Georgia Commerce Bancshares, Inc.
Assets
Cash and cash equivalents	$ 51,059			51,059
Investment securities	139,035			138,229
Loans held for sale	1,249			1,249
Loans	807,726			801,104
Other real estate owned	9,795			5,613
Core deposit intangible	0			7,448
Deferred tax asset, net	5,030			6,879
Other assets	30,587			29,930
Total Assets	1,044,481			1,041,511
Liabilities
Interest-bearing deposits	658,133			658,309
Non-interest-bearing deposits	249,739			249,739
Borrowings	13,203			13,203
Other liabilities	11,236			11,236
Total Liabilities	$ 932,311			932,487
Estimated amortized period for fair value adjustment	60 months
Preliminary Fair Value Adjustment | Florida Bank Group, Inc.
Assets
Cash and cash equivalents			$ 0
Investment securities			136
Loans			(7,073)
Other real estate owned			(75)
Core deposit intangible			4,489
Deferred tax asset, net			9,232
Other assets			(8,949)
Total Assets			(2,240)
Liabilities
Interest-bearing deposits			263
Non-interest-bearing deposits			0
Borrowings			8,598
Other liabilities			4,618
Total Liabilities			$ 13,479
Preliminary Fair Value Adjustment | Old Florida Bancshares, Inc.
Assets
Cash and cash equivalents		$ 0
Investment securities		0
Loans held for sale		0
Loans		(9,342)
Other real estate owned		(2)
Core deposit intangible		10,055
Deferred tax asset, net		3,181
Other assets		(7,238)
Total Assets		(3,346)
Liabilities
Interest-bearing deposits		123
Non-interest-bearing deposits		0
Borrowings		0
Other liabilities		76
Total Liabilities		$ 199
Preliminary Fair Value Adjustment | Georgia Commerce Bancshares, Inc.
Assets
Cash and cash equivalents				0
Investment securities				(806)
Loans held for sale				0
Loans				(6,622)
Other real estate owned				(4,182)
Core deposit intangible				7,448
Deferred tax asset, net				1,849
Other assets				(657)
Total Assets				(2,970)
Liabilities
Interest-bearing deposits				176
Non-interest-bearing deposits				0
Borrowings				0
Other liabilities				0
Total Liabilities				$ 176