EARNINGS PER SHARE (EPS) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
EARNINGS PER SHARE (EPS) [Abstract]
Net income	$ 12,039	$ 11,531	$ 22,609	$ 21,778
Less: Dividends paid on earnings allocated to participating securities	(45)	(46)	(91)	(91)
Income attributable to common stock	11,994	11,485	22,518	21,687
Weighted Average Number Of Shares Outstanding Including Participating Securities Basic	34,975,395	34,181,312	34,899,766	34,113,495
Less: weighted average participating securities	(321)	(329)	(323)	(327)
Weighted average shares outstanding utilized in the calculation of basic EPS	34,975,074	34,180,983	34,899,443	34,113,168
Earnings Per Share, Basic	$ 0.34	$ 0.34	$ 0.65	$ 0.64
Income attributable to common stock	$ 11,994	$ 11,485	$ 22,518	$ 21,687
Weighted average common shares outstanding	34,975,074	34,180,983	34,899,443	34,113,168
Common stock equivalents resulting from the dilutive effect of "in-the-money" stock options	72,989	48,219	64,806	66,928
Weighted average shares outstanding utilized in the calculation of diluted EPS (in shares)	35,048,063	34,229,202	34,964,249	34,180,096
Earnings Per Share, Diluted	$ 0.34	$ 0.34	$ 0.65	$ 0.64
Weighted average shares excluded from earnings per share calculation (in shares)	1,275,586	2,203,024	1,300,026	1,331,331