STOCK BASED COMPENSATION PLANS (Details 3) (Restricted stock, USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Stock based compensation plans
Compensation expense	$ 299,000	$ 327,000
Shares
Unvested at the beginning of the period (in shares)	177,927
Granted (in shares)	72,940	21,993
Vested (in shares)	(31,399)
Unvested at the end of the period (in shares)	219,468
Weighted Average Grant-Date Fair Value
Unvested at the beginning of the period (in dollars per share)	$ 21.38
Granted (in dollars per share)	$ 20.78
Vested (in dollars per share)	$ 21.66
Unvested at the end of the period (in dollars per share)	$ 21.14
Five year specified vesting schedule
Additional disclosure
Numbers of shares expected to vest	12,652	21,993
Vesting period (in years)	5 years	5 years
Percentage of award vesting one third after year three, one third after year four, and one third vesting after year five	33.00%	33.00%
Year in vesting schedule in which one-third of the awards vest, period one	3	3
Year in vesting schedule in which one-third of the awards vest, period two	4	4
Year in vesting schedule in which one-third of the awards vest, period three	5	5
Seven year specified vesting schedule
Additional disclosure
Numbers of shares expected to vest	51,175
Vesting period (in years)	7 years
Percentage of award vesting one third after year five, one third after year six, and one third vesting after year seven	33.00%
Year in vesting schedule in which one-third of the awards vest, period one	5
Year in vesting schedule in which one-third of the awards vest, period two	6
Year in vesting schedule in which one-third of the awards vest, period three	7
Five year ratable vesting
Additional disclosure
Numbers of shares expected to vest	9,113
Vesting period (in years)	5 years