CASH FLOWS STATEMENTS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net Income (Loss) Attributable to Parent	$ 654	$ 2,960
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation, Depletion and Amortization	7,434	6,889
Stock-based compensation expense	2,683	2,449
Increase (Decrease) in Deferred Income Taxes	1,053	(8,087)
Gain (Loss) on Disposition of Property Plant Equipment	47	94
Income (Loss) from Equity Method Investments	(614)	0
Other Operating Activities, Cash Flow Statement	(138)	(242)
Changes in operating assets and liabilities:
Accounts receivable	(8,075)	(7,342)
Inventories	(1,510)	(486)
Operating Assets	(501)	2,272
Operating Liabilities	(6,134)	(10,400)
Accounts payable	(4,186)	4,117
Unearned revenue	843	680
Net cash from operations	(7,216)	(7,096)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Common stock issued	1,349	802
Payments Related to Tax Withholding for Share-based Compensation	(2,310)	(2,072)
Common stock cash dividends paid	(4,063)	(2,696)
Net cash used in financing	(5,024)	(3,966)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Additions to property and equipment	(3,923)	(3,823)
Payments for (Proceeds from) Businesses and Interest in Affiliates	(22)	0
Net cash used in investing	(3,901)	(3,823)
Effect of foreign exchange rates on cash and cash equivalents	45	133
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	(16,096)	(14,752)
Cash and cash equivalents, end of period	$ 43,077	$ 61,689