EARNINGS PER SHARE DATA (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basic [Abstract]
Weighted average shares outstanding (in shares)	14,395	14,328
Net income	$ 13,232	$ 11,646
Convertible preferred stock dividend	23	23
Net income attributable to common shareholders	13,209	11,623
Per share amount (in dollars per share)	$ 0.92	$ 0.81
Diluted [Abstract]
Weighted average shares outstanding (in shares)	14,395	14,328
Assumed conversion of convertible preferred stock (in shares)	840	840
Total dilutive shares (in shares)	15,235	15,168
Net income attributable to common shareholders	13,209	11,623
Convertible preferred stock dividend	23	23
Net income for diluted earnings per share	$ 13,232	$ 11,646
Per share amount (in dollars per share)	$ 0.87	$ 0.77