COMMON STOCK AND EARNINGS PER SHARE (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
COMMON STOCK AND EARNINGS PER SHARE
Weighted-average number of common shares outstanding - basic	47,764,462	47,376,605	47,725,186	47,314,810
Potentially dilutive shares resulting from stock plans	724,000	696,000	716,000	718,000
Weighted-average number of common shares outstanding - diluted	48,487,623	48,072,632	48,441,129	48,032,710
Antidilutive equity awards, number of shares not included in the weighted-average common shares - diluted	0	124,000	0	144,000
Earnings per share, other disclosures
Repurchase of common stock, shares			345,963	388,938
Purchase of common stock for treasury			$ 7,478	$ 6,412
Exercise of stock options, shares			348,671	211,057
Dividends, Common Stock, Cash			$ 17,684
Proceeds from the issuance of common stock			$ 5,247	$ 2,788
Vested (in shares)			276,164	496,191
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,136		273,560