Parent Company Only Financial Statements - Schedule Of Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and due from banks	$ 28,140	$ 26,471
Goodwill	4,808	4,808	4,808
Other assets	23,781	20,915
Total assets	3,286,617	2,670,867
Liabilities and shareholders' equity
Long-term borrowings	55,110	75,220
Other liabilities	27,777	15,373
Total liabilities	2,904,758	2,422,765
Total shareholders' equity	381,859	248,102	223,516	131,033
Total liabilities and shareholders' equity	3,286,617	2,670,867
First NBC Bank Holding Company [Member]
Assets
Cash and due from banks	23,990	3,709
Goodwill	841	841
Investments in subsidiaries	355,068	260,618
Other assets	2,123	3,157
Total assets	382,022	268,325
Liabilities and shareholders' equity
Long-term borrowings	110	20,220
Other liabilities	53	4
Total liabilities	163	20,224
Total shareholders' equity	381,859	248,101
Total liabilities and shareholders' equity	$ 382,022	$ 268,325