REVENUE, Disclosure of Impact of Adoption on Balance Sheet and Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Assets [Abstract]
Unbilled receivables	$ 15,587		$ 15,587		$ 0
Inventories	106,448		106,448		107,719
Liabilities [Abstract]
Other current liabilities	5,077		5,077		6,204
Equity [Abstract]
Retained earnings	154,985		154,985		147,807
Statement of Operations [Abstract]
Net sales	140,710	$ 131,617	258,961	$ 245,285
Cost of sales	111,696	102,490	208,814	192,795
Operating income	10,667	7,266	11,104	9,621
Provision for income taxes	2,399	2,292	2,724	2,269
Net earnings	6,634	$ 3,120	5,332	$ 3,866
ASU 2014-09 [Member]
Assets [Abstract]
Unbilled receivables					14,536
Inventories					96,675
Liabilities [Abstract]
Other current liabilities					6,247
Equity [Abstract]
Retained earnings					151,256
Balances Without Adoption of ASC 606 [Member] | ASU 2014-09 [Member]
Assets [Abstract]
Unbilled receivables	0		0
Inventories	117,780		117,780
Liabilities [Abstract]
Other current liabilities	4,918		4,918
Equity [Abstract]
Retained earnings	150,889		150,889
Statement of Operations [Abstract]
Net sales	138,777		257,911
Cost of sales	110,321		208,526
Operating income	10,109		10,342
Provision for income taxes	2,343		2,608
Net earnings	6,132		4,686
Effect of Change Higher/(Lower) [Member] | ASU 2014-09 [Member]
Assets [Abstract]
Unbilled receivables	15,587		15,587		14,536
Inventories	(11,332)		(11,332)		(11,044)
Liabilities [Abstract]
Other current liabilities	159		159		43
Equity [Abstract]
Retained earnings	4,096		4,096		$ 3,449
Statement of Operations [Abstract]
Net sales	1,933		1,050
Cost of sales	1,375		288
Operating income	558		762
Provision for income taxes	56		116
Net earnings	$ 502		$ 646