Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2025	Jun. 28, 2024
Cash flows from operating activities:
Net income	$ 42,838	$ 32,445
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, and amortization	34,047	32,698
Amortization of deferred financing costs in interest expense	1,412	857
Stock-based compensation expense (non-cash)	5,437	5,334
Deferred income tax expense (benefit)	(25)	926
Changes in assets and liabilities:
Accounts receivable	(949)	5,274
Inventory	94	(24,312)
Prepaid and other current assets	(3,029)	(12,494)
Accounts payable and accrued expenses	4,193	(20,863)
Unearned revenue	(8,525)	(10,340)
Interest and taxes payable	(1,230)	(3,906)
Other-net	(8,821)	858
Net cash provided by operating activities	65,442	6,477
Cash flows from investing activities:
Payments for purchase of property, plant, and equipment	(25,003)	(38,412)
Payments for mine development	(10,175)	(10,375)
Proceeds from sale of property, plant, and equipment	266	527
Net cash used in investing activities	(34,912)	(48,260)
Cash flows from financing activities:
Proceeds from borrowings under credit facilities, net	(2,219)	73,649
Repayment of long-term debt	(15,111)	(15,172)
Principal payments under finance lease obligations	(306)	(382)
Cash dividends paid	(5,705)	(5,493)
Deferred financing costs	(2,856)	0
Repurchase of common stock	(7,843)	0
Payments of withholding taxes for stock-based compensation awards	(2,337)	(6,402)
Net cash provided by/(used in) financing activities	(36,377)	46,200
Effects of exchange rate changes	1,725	(613)
Net change in cash and cash equivalents	(4,122)	3,804
Cash and cash equivalents at beginning of period	16,713	13,294
Cash and cash equivalents at end of period	$ 12,591	$ 17,098