LOANS - Troubled debt restructurings (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) Integer	Sep. 30, 2016 USD ($) Integer
Business Activities Loans - Residential real estate
Quantity of troubled debt restructurings | Integer		4
Pre-modification balance		$ 683
Post-modification balance		$ 683
Business Activities Loans - Commercial real estate
Quantity of troubled debt restructurings | Integer	1	2
Pre-modification balance	$ 600	$ 2,123
Post-modification balance	$ 600	$ 2,123
Business Activities Loans - Troubled debt restructurings
Quantity of troubled debt restructurings | Integer	1	6
Pre-modification balance	$ 600	$ 2,806
Post-modification balance	$ 600	$ 2,806
Business Activities Loans - Rate reduction and term extension
Quantity of troubled debt restructurings | Integer		1
Pre-modification balance		$ 174
Post-modification balance		$ 174
Business Activities Loans - Debt consolidation
Quantity of troubled debt restructurings | Integer		2
Pre-modification balance		$ 2,123
Post-modification balance		$ 2,123
Business Activities Loans - Term extension
Quantity of troubled debt restructurings | Integer	1	3
Pre-modification balance	$ 600	$ 509
Post-modification balance	$ 600	$ 509