EARNINGS PER SHARE (Computation of Basic and Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
EARNINGS PER SHARE [Abstract]
Net income	$ 5,662		$ 6,583
Dividends and undistributed earnings allocated to participating securities	(10)	[1]	(11)	[1]
Net income loss available to common shareholders	$ 5,652		$ 6,572
Weighted-average common shares outstanding for basic EPS	7,627,691		7,672,039
Dilutive effect of stock-based awards	15,576		14,894
Weighted-average common and potential common shares for diluted EPS	7,643,267		7,686,933
Basic EPS	$ 0.74		$ 0.86
Diluted EPS	$ 0.74		$ 0.86

[1] Represents dividends paid and undistributed earnings allocated to nonvested restricted stock awards.