NET EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Net Earnings - Basic and Diluted	$ 20,676	$ 19,829	$ 18,783	$ 19,214	$ 19,679	$ 19,346	$ 59,288	$ 58,239
Weighted average common shares - basic (in shares)	32,094,000			32,141,000			32,164,000	32,068,000
Effect of dilutive securities - stock options, restricted stock, and performance shares (in shares)	361,000			424,000			350,000	384,000
Weighted average common shares - diluted (in shares)	32,455,000			32,565,000			32,514,000	32,452,000
Net earnings per share - basic (in dollars per share)	$ 0.64			$ 0.60			$ 1.84	$ 1.82
Net earnings per share - diluted (in dollars per share)	$ 0.64			$ 0.59			$ 1.82	$ 1.79
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)							183,822	0