NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Earnings (Numerator) [Abstract]
Basic EPS - Net earnings	$ 14,150	$ 14,916	$ 26,036	$ 30,088
Diluted EPS - Net earnings	$ 14,150	$ 14,916	$ 26,036	$ 30,088
Number of Shares (Denominator) [Abstract]
Basic EPS - weighted average common shares outstanding (in shares)	31,476,298	31,111,155	31,441,545	30,976,681
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	398,886	521,119	401,052	547,925
Diluted EPS - weighted average common shares outstanding and effect of stock options, restricted stock and performance shares (in shares)	31,875,184	31,632,274	31,842,597	31,524,606
Per Share Amount [Abstract]
Basic EPS - Net earnings (in dollars per share)	$ 0.45	$ 0.48	$ 0.83	$ 0.97
Diluted EPS - Net earnings (in dollars per share)	$ 0.44	$ 0.47	$ 0.82	$ 0.95
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)			531,132	259,872