Note 16 - Business Combination (Details Textual) - Farmers National Banc Corp [Member] - Cortland Savings and Banking Company [Member]	Jun. 22, 2021 $ / shares
Business Combination, Consideration Transferred, Cash Option, Price Per Share (in dollars per share)	$ 28.00
Business Combination, Consideration Transferred, Share Conversion Option, Exchange Ratio	1.75
Business Combination, Share Conversion, Percentage of Acquiree's Outstanding Shares, Maximum	75.00%

The per share amount of cash that the shareholders of acquiree will receive in a business combination when cash option is elected.

No definition available.

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Namespace Prefix:	cldb_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration