Subordinated Debentures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Subordinated Borrowings [Abstract]
Value of subordinated debentures received by Trust	$ 5.2
Floating interest rate on subordinated debentures	3.10%

Floating interest rate on subordinated debentures.

No definition available.

Name:	cnob_FloatingInterestRateOnSubordinatedDebentures
Namespace Prefix:	cnob_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration