NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share, Basic and Diluted [Abstract]
Net Earnings - Basic and Diluted	$ 22,731	$ 23,411	$ 21,125	$ 19,768	$ 46,142	$ 40,893
Weighted average common shares - basic (in shares)	32,232,000		32,180,000		32,243,000	32,158,000
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	419,000		290,000		410,000	334,000
Weighted average common shares - diluted (in shares)	32,651,000		32,470,000		32,653,000	32,492,000
Net earnings per share - basic (in dollars per share)	$ 0.71		$ 0.66		$ 1.43	$ 1.27
Net earnings per share - diluted (in dollars per share)	$ 0.70		$ 0.65		$ 1.41	$ 1.26
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)	153,868		377,573		304,324	212,271