NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Basic and Diluted [Abstract]
Net Earnings - Basic and Diluted	$ 21,568	$ 21,125	$ 19,768	$ 20,676	$ 19,829	$ 18,783	$ 62,461	$ 59,288
Weighted average common shares - basic (in shares)	32,206,000			32,094,000			32,174,000	32,164,000
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	310,000			361,000			326,000	350,000
Weighted average common shares - diluted (in shares)	32,516,000			32,455,000			32,500,000	32,514,000
Net earnings per share - basic (in dollars per share)	$ 0.67			$ 0.64			$ 1.94	$ 1.84
Net earnings per share - diluted (in dollars per share)	$ 0.66			$ 0.64			$ 1.92	$ 1.82
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)	172,122			183,822			215,271	196,382