Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 66,425	$ 84,939
Accounts receivable, net of allowance for doubtful accounts of $912 and $1,036, respectively	86,917	71,372
Inventories	116,170	100,133
Unbilled receivables	18,277	14,135
Assets held for sale	1,635	0
Other current assets	10,003	9,637
Total current assets	299,427	280,216
Property, plant and equipment, net	36,747	34,501
Right-of-use assets	11,066	14,217
Intangible assets, net	62,655	65,789
Goodwill	28,178	23,966
Deferred income taxes	5,096	5,705
Other assets	30,710	29,472
Total assets	473,879	453,866
Current Liabilities:
Accounts payable	53,020	39,774
Accrued expenses	33,470	28,476
Current portion of long-term debt	8,273	5,286
Operating lease liabilities, current	5,980	6,591
Other current liabilities	4,350	7,409
Total current liabilities	105,093	87,536
Long-term Liabilities:
Long-term debt	104,656	110,294
Operating lease liabilities, long-term	5,351	8,064
Liability for uncertain tax positions	26,864	26,089
Minimum pension obligation and unfunded pension liability	25,013	24,620
Deferred income taxes	1,061	1,030
Other liabilities	9,243	10,434
Total liabilities	277,281	268,067
Commitments and contingencies (see Note 13)
Stockholders' Equity:
Preferred stock, no par value, 1,000,000 shares authorized; none issued	0	0
Additional paid-in capital	37,328	36,136
Retained earnings	175,883	166,491
Accumulated other comprehensive loss	(17,854)	(18,063)
Total stockholders' equity	196,598	185,799
Total liabilities and stockholders' equity	473,879	453,866
Common Class A [Member]
Stockholders' Equity:
Common stock	214	214
Common Class B [Member]
Stockholders' Equity:
Common stock	$ 1,027	$ 1,021