EARNINGS PER SHARE DATA (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Basic [Abstract]
Weighted average shares outstanding (in shares)	14,451	14,392	14,424	14,360
Net income	$ 13,749	$ 12,177	$ 26,981	$ 23,823
Convertible preferred stock dividend	22	22	45	45
Net income attributable to common shareholders	13,727	12,155	26,936	23,778
Per share amount (in dollars per share)	$ 0.95	$ 0.84	$ 1.87	$ 1.66
Diluted [Abstract]
Weighted average shares outstanding (in shares)	14,451	14,392	14,424	14,360
Assumed conversion of convertible preferred stock (in shares)	840	840	840	840
Total dilutive shares (in shares)	15,291	15,232	15,264	15,200
Net income attributable to common shareholders	13,727	12,155	26,936	23,778
Convertible preferred stock dividend	22	22	45	45
Net income for diluted earnings per share	$ 13,749	$ 12,177	$ 26,981	$ 23,823
Per share amount (in dollars per share)	$ 0.90	$ 0.80	$ 1.77	$ 1.57