NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share, Basic and Diluted [Abstract]
Net Earnings - Basic and Diluted	$ 21,125	$ 19,768	$ 19,829	$ 18,783	$ 40,893	$ 38,612
Weighted average common shares - basic (in shares)	32,180,000		32,209,000		32,158,000	32,198,000
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	290,000		374,000		334,000	342,000
Weighted average common shares - diluted (in shares)	32,470,000		32,583,000		32,492,000	32,540,000
Net earnings per share - basic (in dollars per share)	$ 0.66		$ 0.62		$ 1.27	$ 1.20
Net earnings per share - diluted (in dollars per share)	$ 0.65		$ 0.61		$ 1.26	$ 1.19
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)	377,573		185,922		212,271	368,612