STOCK PLANS (Details 3) - Stock options - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Options
Outstanding at beginning of year (in shares)	647,671	1,023,389	1,364,284
Exercised (in shares)	(377,671)	(375,718)	(330,895)
Forfeited (in shares)			(10,000)
Outstanding at end of year (in shares)	270,000	647,671	1,023,389	1,364,284
Exercisable at end of year (in shares)	262,000
Weighted-Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 15.37	$ 14.48	$ 13.84
Exercised (in dollars per share)	14.98	12.93	11.98
Forfeited (in dollars per share)			10.24
Outstanding at end of year (in dollars per share)	15.93	$ 15.37	$ 14.48	$ 13.84
Exercisable at end of year (in dollars per share)	$ 15.93
Weighted- Average Remaining Contractual Life (years)
Outstanding at end of year	1 year 5 months 9 days	2 years 1 month 28 days	2 years 8 months 16 days	3 years 6 months 11 days
Exercisable at end of year	1 year 3 months 19 days
Aggregate Intrinsic Value
Outstanding at beginning of year	$ 4,016,809	$ 4,625,520	$ 3,686,098
Exercised	2,496,218	2,237,704	1,739,700
Forfeited			42,400
Outstanding at end of year	1,203,600	$ 4,016,809	$ 4,625,520	$ 3,686,098
Exercisable at end of year	$ 1,181,040