Loans - Summary of Information on TDRs Modification (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Receivables [Abstract]
Maturity and interest rate adjustment	$ 925	$ 609
Movement to or extension of interest rate-only payments	597	1,333
Other concession(s)	344	394
Total	$ 1,866	$ 2,336

Financing Receivable Modifications Extension Of Interest Rate Only Payments

No definition available.

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Namespace Prefix:	nbcb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration