Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 85,990	$ 72,474	$ 15,462
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization	53,436	44,137	42,384
Amortization of deferred financing costs in interest expense	1,734	967	790
Stock-based compensation expense (non-cash)	8,813	6,517	5,528
Amortization of pension and post-retirement costs	(146)	437	(151)
Loss (gain) on sale of property, plant, and equipment	14	(282)	466
Deferred income tax (benefit) expense	1,733	(12,957)	(9,850)
Impairment charges	0	0	10,472
Net pension curtailments and settlements	(551)	0	94
Changes in assets and liabilities, net of acquired assets and liabilities:
Decrease (increase) in accounts receivable	(4,377)	(30,490)	(707)
Decrease (increase) in inventory	(63,986)	(43,458)	(1,288)
Decrease (increase) in prepaid and other current assets	(1,604)	(3,855)	2,475
Increase (decrease) in accounts payable and accrued expenses	12,860	40,219	(21,877)
Increase (decrease) in unearned revenue	207	106	2,935
Increase (decrease) in interest and taxes payable	154	(220)	(157)
Increase (decrease) in unearned income due to customer prepayments	21,942	13,752	54,103
Other — net	(261)	2,894	378
Net cash provided by operating activities	115,958	90,241	101,057
Cash flows from investing activities:
Payments for acquisition, net of cash acquired	(2,971)	(392,240)	(130,715)
Payments for purchase of property, plant, and equipment	(77,608)	(102,910)	(67,274)
Proceeds from settlement of currency exchange contract	0	0	3,249
Proceeds from sale of property, plant, and equipment	850	881	33
Net cash used in investing activities	(79,729)	(494,269)	(194,707)
Cash flows from financing activities:
Proceeds from (repayments of) borrowings under revolving credit agreement, net	(9,046)	118,297	34,000
Proceeds from issuance of debt	9,276	300,000	0
Repayment of debt	(19,299)	(2,054)	(20,634)
Principal payments under finance lease obligations	(2,736)	(2,819)	(2,213)
Cash dividends paid	(10,160)	(9,697)	(9,257)
Deferred financing costs	0	(7,403)	0
Repurchase of common stock	0	0	(6,766)
Payments for withholding taxes for stock-based compensation awards	(3,593)	(3,318)	(2,221)
Net cash provided by (used in) financing activities	(35,558)	393,006	(7,091)
Effects of exchange rate changes	(2,032)	(394)	1,612
Net change in cash and cash equivalents	(1,361)	(11,416)	(99,129)
Cash and cash equivalents at beginning of period	14,462	25,878	125,007
Cash and cash equivalents at end of period	$ 13,101	$ 14,462	$ 25,878