NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Net Earnings - Basic and Diluted	$ 19,829	$ 18,783	$ 19,679	$ 19,346	$ 38,612	$ 39,025
Weighted average common shares - basic (in shares)	32,208,851		32,077,353		32,198,660	32,031,342
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	373,694		360,366		341,826	346,324
Weighted average common shares - diluted (in shares)	32,582,545		32,437,719		32,540,486	32,377,666
Net earnings per share - basic (in dollars per share)	$ 0.62		$ 0.61		$ 1.20	$ 1.22
Net earnings per share - diluted (in dollars per share)	$ 0.61		$ 0.61		$ 1.19	$ 1.21
Stock Options
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)					185,922	190,590