CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
OPERATING ACTIVITIES:
Net income	$ 8,668	$ 7,031
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	5,250	5,341
Amortization of deferred financing costs	2	2
Deferred income taxes	438	750
(Gain) loss on disposition of property, plant and equipment	(52)	3
Stock-based compensation	651	547
Changes in operating assets and liabilities:
Trade receivables, net	(5,678)	(978)
Inventories, net	(1,255)	(199)
Prepaid expenses and other current assets	992	(183)
Other assets	6	16
Accounts payable and accrued expenses	(988)	(719)
Other liabilities	25	11
Net cash provided by operating activities	8,059	11,622
INVESTING ACTIVITIES:
Purchase of property, plant and equipment	(5,517)	(4,543)
Acquisition of a business	(5,889)
Proceeds from sale of property, plant and equipment	75	10
Net cash used in investing activities	(11,331)	(4,533)
FINANCING ACTIVITIES:
Cash dividends paid	(1,133)	(905)
Purchase of treasury shares	(86)	(95)
Net cash used in financing activities	(1,219)	(1,000)
Net (decrease) increase in cash and cash equivalents	(4,491)	6,089
Cash and cash equivalents at beginning of period	105,355	83,562
Cash and cash equivalents at end of period	$ 100,864	$ 89,651