Loans - Schedule of Carrying Amount of Loans Acquired (Detail) - Florida Bank Group, Inc., Old Florida Bancshares, Inc., Georgia Commerce Bancshares, Inc. - Acquired Impaired Loans - Receivables Acquired With Deteriorated Credit Quality $ in Thousands	Sep. 30, 2016 USD ($)
Accounts, Notes, Loans and Financing Receivable
Contractually required principal and interest at acquisition	$ 76,445
Non-accretable difference (expected losses and foregone interest)	(11,867)
Cash flows expected to be collected at acquisition	64,578
Accretable yield	(6,823)
Basis in acquired loans at acquisition	$ 57,755