FINANCIAL INSTRUMENTS - Financial instrument liabilities with off-balance sheet credit risk (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Investments, All Other Investments [Abstract]
Residential	$ 1,060	$ 1,559
Home equity credit	29,989	30,929
Commercial	2,279	6,650
Land	300	290
Real estate secured	33,628	39,428
Commercial and industrial	15,441	11,715
Consumer	1,349	1,358
Unadvanced portions of loans	50,418	52,501
Commitments to originate loans	17,727	5,860
Standby letters of credit	34	34
Total	$ 68,179	$ 58,395