Loans and Allowance for Loan Losses (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Loans and Allowance for Loan Losses (Textual) [Abstract]
Period after which loans considered nonperforming	90 days
Potential problem loans	$ 3.9	$ 2.7

Minimum period after which loans to be considered non performing.

No definition available.

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Namespace Prefix:	cldb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration