NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net Earnings (Numerator) [Abstract]
Basic EPS - Net earnings	$ 14,012	$ 13,976	$ 40,048	$ 44,063
Diluted EPS - Net earnings	$ 14,012	$ 13,976	$ 40,048	$ 44,063
Number of Shares (Denominator) [Abstract]
Basic EPS - weighted average common shares outstanding (in shares)	31,566,067	31,309,710	31,483,053	31,087,691
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	412,736	408,449	404,209	492,701
Diluted EPS - weighted average common shares outstanding and effect of stock options, restricted stock, and performance shares (in shares)	31,978,803	31,718,159	31,887,262	31,580,392
Per Share Amount [Abstract]
Basic EPS - Net earnings (in dollars per share)	$ 0.44	$ 0.45	$ 1.27	$ 1.42
Diluted EPS - Net earnings (in dollars per share)	$ 0.44	$ 0.44	$ 1.26	$ 1.40
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive stock options outstanding, excluded from diluted earnings per share calculation (in shares)			332,560	260,872